In a shallow glass dish, combine the sherry, soy sauce, sesame oil, and ginger. Place the fish in the marinade for 30 minutes.
Preheat the grill, and brush the grids with vegetable oil. Dot the salmon with butter, and grill on MEDIUM – HIGH for 10 minutes. The skin should easily separate from the fish when it is cooked. Place the salmon on a platter, garnish with fresh lemon slices and serve.