The most common marinade for tuna steak is an Asian-inspired solution that typically contains 1/2 cup soy sauce, 1/3 cup rice wine vinegar and 1 1/2 inches of grated fresh ginger. Anne Burrell from Food Network adds two cloves of chopped garlic and four scallions to her marinade.
Martha Stewart sweetens her Japanese tuna steak marinade by adding 2 tablespoons of sugar to the soy sauce solution. Marinate the steaks in the refrigerator for 15 minutes to 2 hours.
For tuna steaks with a lemony flavor, rub with garlic, salt and pepper, drizzle with olive oil, and place the steaks in a large freezer bag with lemon zest. Allow the tuna to marinate overnight before grilling.