Heat the grill.
Rinse tuna filets under cold water; pat dry with paper towels.
Place the sesame seeds in a small hot skillet for about 1 minute, shaking the skillet gently, until just browned. Remove immediately from heat. Place in a small bowl.
Add the remaining ingredients to the bowl. Brush this mixture onto both sides of tuna filets and grill to desired doneness, turning once.
It is a good idea to remove tuna BEFORE it is to the desired doneness. It will continue to cook and will be dry if overcooked.
(Yields 4 servings)
1 serving: 18 g. fat (before cooking); trace carb.; 36 g. protein; trace fibre