Herring has been one of my favorite snacks ever since I was little. A common way of preserving herring in Russia and Ukraine is in salt brine. Herring there is commonly preserved whole in barrels in a salted water solution with various spices. A similar method is used by the Dutch, except the fish used is younger and it is pickled for a shorter time.
A common misconception about this way of preserving herring is that it is "raw." The salt brine (which is sometimes so strong that the fish has to be desalted) has the effect of pickling or "curing" the fish and is therefore a method of preservation of the herring, so the fish is not actually eaten raw in the ordinary sense of the word. This herring is "raw" in the same way that smoked salmon can be considered "raw:" the raw flesh of each fish is preserved using either the salt or a cold-smoking process, respectively, prior to being consumed. In neither instance is it cooked prior to consumption.
The best herring I've ever had was in the Netherlands. When we visited Amsterdam, we knew ahead of time from a guidebook that there are stands sprinkled all around town, as abundant as perhaps hot dog stands around big cities in the U.S., that serve on a long, split bun, with pickles and onions, not hot dogs, but young herring fillets. We got hooked on the first try and continued to have two or more a day, every day we were there.
As an aside, anyone willing to open a herring stand in New Amsterdam will be my personal hero.
When we were living in Norway, almost every store, no matter how small, had packaged herring fillets preserved in salt brine (which typically had to be desalted by soaking them in water). More popular however, was jarred herring (along with big plastic white buckets of it) which is preserved in vinegar and sugar, with barely any salt. This Scandinavian treat can be eaten as a snack, a meal with potatoes, or even for lunch as an open-faced sandwich. If you want to try something similar, pick up a jar of Swedish herring at IKEA.
Herring is also often served at a Russian table as an appetizer (or "zakuska"). The herring fillets are sliced into bite-size pieces and served, sprinkled with onion slices or bits of scallion. This way it is sometimes used as a vodka chaser. It is also common to put it in salads. One of the more famous Russian salads, which is a layered herring and root vegetable salad, is called "Herring Under a Coat." For all of these purposes, a whole herring would typically be used. If you have a Russian store nearby you, you might be in luck. There you'll be sure to find packaged salted fillets (you might have to ask at the counter if you want it whole). And if you do get your hand's on a whole one, let's figure out what to do with it.
How to fillet a herring (and other small fish):
Rinse the fish under cold water and pat dry with paper towels. If the fish has not been gutted, using a sharp knife, slice lengthwise along the belly of the fish. Remove and discard the innards. Rinse the inside of the fish under cold water and pat dry. Place the fish on a clean work surface.
Slice off the head slightly behind the gills. Then turn the back of the fish to face you and make an incision along the spine of the fish deep enough to reach the backbone. Cut off and discard the back fin.
With the fish still on its side, insert the blade of your knife between the flesh and the skin. Then carefully peel back the skin to remove it. Repeat with the other side, discarding the skin.
Run the knife between the flesh and the rib bones of the fish on each side to separate the fillet from the bones, cutting off the fillet at the tail. Discard the spine. With the salted herring, it is easier to separate the the fillets, which can be achieved by simply peeling off the fillet from the bones.
Once you have two fillets ready, scrape the inside of each fillet with a knife to remove any gunk. Run your fingers along the insides of each fillet and using either your fingers or tweezers, pluck away any bones left in the flesh. At this point, your fillets are ready.
If you are preparing the salted herring for storing or serving, slice each fillet of the herring crosswise into one inch pieces.
How to store herring:
Once you've filleted and sliced the herring, you can use this method of storing it if you are not serving it immediately. Place the sliced fillets into a shallow ceramic or glass dish (metal can react and plastic tends to absorb the fish smell). Chop some white onion and sprinkle it on top of the fish. Then pour enough oil over the fish to cover it, using either vegetable or canola oil. The oil acts as a preservant of sorts, by sealing away moisture and air. Then cover tightly and refrigerate. The fish will keep this way, refrigerated, for several days.
How to serve herring (the Russian way):
To serve the herring, place the sliced fillets on an elongated serving platter, sprinkle with onion or scallion, and drizzle with vegetable or canola oil. Serve as an appetizer with some bread or boiled potatoes, along with other appetizers (or "zakuski") and salads.
I realize that in many places outside of those mentioned, this type of herring is not easily available. For instance, most U.S. food stores only sell jarred herring pickled in vinegar or as canned "kippers." I have been able to find herring fillets preserved in brine (or preserved whole) here only in specialty or Russian food shops. I personally find herring pickled in vinegar unappealing. Herring is very delicate, the taste is faint but unmistakable, a little bit smokey, buttery, tender. Because of its delicate taste, vinegar can significantly overpower the taste so that the actual flavor of herring is lost and you are left eating vinegary pieces of anonymous fish.
However, if this is your only access to herring, try it anyway. Rinse the pieces or soak them in water first. You can then serve the herring in the same way with fresh onion or scallion, and it would work quite well in the upcoming Russian layered herring salad.