Trim the salmon and remove the pin bones. Place the salmon on several large sheets of cling wrap. Combine the vodka or sake, sugar, salt, vanilla bean seeds and lemon zest and rub the mixture into the salmon flesh. Cover the salmon with the cling wrap and place it in a shallow ceramic or glass dish. Place another flat ceramic or glass dish on top of the salmon and weight the top dish with several heavy cans. Refrigerate it for 2 days. Once the salmon is cured it will be firm and an intense dark pink. Wash off the cure mixture and pat the salmon dry with paper towels. Slice into paper-thin slices against the salmon’s natural grain to serve.