Before you begin, place the salmon and corvina in the freezer for 15 minutes to make it easier to cut. Then, cut the fish into cubes and mix with the lemon zest, shallot, chives, a little oil, salt and pepper. Let the mixture stand in the fridge.
For the cookies, in a nonstick skillet put the cheese slices one at a time until very browned. Remove from the heat and let cool. When cold, they will be crunchy like a cookie. Put some tartare on top of each cookie and serve.