Prepare marinade by combining soy sauce, sugar, garlic, and ginger in a small bowl.

Place salmon fillets in a large, Ziploc and pour the marinade over it. Seal, and refrigerate for at least 3 hours, turning occasionally to ensure the marinade covers all of the fish.

Preheat oven to 425 degrees.

Seal salmon in aluminum foil, place on a baking sheet, and place in oven.

Cook for 15 minutes, or until salmon is cooked through and flakes easily with a fork. Serve immediately.