Place salmon on a cutting board and cut it into small pieces. Next take meat cleaver and chop the fish into even smaller pieces.
In a medium bowl, place minced salmon, corn, bread crumbs, beat egg, salt, pepper, garlic powder, green onions, and milk and mix well with hands. Let the mixture rest for 5 minutes.
Divide the fish mixture to 8. Place vegetable oil on your palms and shape the fish mixture into hamburger shapes and set them aside.
Heat a frying pan large enough to hold all salmon cakes, add about 1 tablespoon of cooking oil and pan-fry the fish. Turn the salmon and cook the other side for another minute. Turn the heat low, add 2 tablespoon of sake or wine (if using) then cover the pan and cook through the fish, about another minute.
Plate the salmon cakes on individual dishes. Serve the salmon cake hot with homemade tartar sauce and wedge of lemon.