PREPARATION:
- Prepare Citrus Marinade; combine with tuna in large resealable food storage bag. Seal bag; turn to coat. Marinate in refrigerator 1 hour, turning occasionally.* Drain tuna; discard marinade.
*Marinate in refrigerator 1 hour for each inch of thickness.
- Spray cold grid of grill with nonstick cooking spray. Prepare coals for direct grilling.
- Place tuna on grid, 4 inches from hot coals. Grill 8 to 10 minutes or until tuna flakes easily when tested with fork, turning once during grilling. (Or, place tuna on rack of broiler pan coated with nonstick cooking spray. Broil 4 inches from heat, 8 to 10 minutes or until tuna flakes easily when tested with fork, turning once during broiling.) Slice tuna into 1/4-inch-thick slices; set aside.
- Place 2 cups water in large saucepan; bring to a boil over high heat. Add beans; cook 2 minutes. Drain; rinse with cold water and drain again.
- Place lettuce on large serving platter. Arrange tuna, beans, potatoes, tomato, egg whites and onion on lettuce. Sprinkle each serving with olives. Serve with fat-free salad dressing, if desired.
