Rub the albacore steaks with 4 tablespoons sugar. Allow to sit 30 minutes in the refrigerator.
In a skillet over medium heat, toast the sesame seeds 5 minutes, or until lightly browned.
In a shallow bowl, mix the remaining sugar, toasted sesame seeds, green onion, garlic, ginger, soy sauce, sesame oil, salt, and pepper. Place the albacore steaks in the mixture, and marinate 2 hours in the refrigerator.
Preheat the oven broiler.
Discard marinade, and place the albacore steaks on a baking sheet. Broil to desired doneness in the preheated oven.