In a small bowl combine honey, soy sauce and sesame oil. Pour over tuna steaks and let marinate at room temperature while you light the grill. Remove steaks from marinade and grill 5 -7 minutes per side. Set tuna aside to cool slightly. Break tuna into bite size chunks; add onions, celery, salt , pepper, lemon juice and mayo. Chill. Pile high on slices of grilled bread and enjoy.
Makes 4-6 sandwiches depending on size of bread and your appetite