In a mixing bowl, combine the salt, dill, zest, black pepper, vodka, and sugar together. Place the salmon, skin side down, on several large sheets of plastic wrap. Cover the entire salmon with the curing mixture, packing the cure into the salmon. Wrap the salmon completely and tightly in the plastic wrap and place the salmon, skin side down on a 1/2 sheet pan. Place something heavy like a skillet, weights, or a brick (which needs to be wrapped in plastic wrap). This will help infuse the salmon into the mixture. Refrigerate the salmon for 24 hours. Remove the salmon from the refrigerator and wipe off the salt mixture. Rinse the salmon under cold water, removing all the cure. Using a sharp knife, slice the salmon diagonally paper thin. Small dice the salmon. In a mixing bowl, toss the salmon with the red onions and chervil and a drizzle of olive oil. Season with black pepper. Spoon about 1/4 cup of the mixture into each pastry. Garnish with caviar.