My favorite tapa in Spain. I have tried to make it here, and even though I haven't found "boquerones" (a little blue fish from the Mediterranean) in New York, it can actually work with anchovies.
Clean the anchovies/boquerones under water. Get rid of the heads and open the clean anchovies/boquerones as if they were books. Get rid of the insides of the fish and after rinsing them, place them in in a deep tray.
Once you have the tray covered with "open book" fish, sprinkle some sea salt and cover them with the white vinegar.
Put them in the fridge for a minimum of 12 hours. I usually let them sometime between 12 to 18 hours.
Once the macerating is done, cut a couple of cloves of garlic in really thin slices (it depends a lot on how much fish you have and how much you like garlic). Put aside.
Chop parsley in really small pieces.
Get each fish out of the tray where they have been macerating. Arrange them nicely in another tray.
Once they are arranged sprinkle the cut garlic and the parsley over the fish.
Cover with good Spanish virgin olive oil.
Enjoy with white wine and Italian bread or a baguette.
The prep time varies depending on your fish cleaning and cutting skill.