Combine marinade ingredients in small bowl. Place steak and 1/2 cup marinade in a food-safe plastic bag; turn steak to coat. Close bag securely; turn steak to coat. Marinate steak in refrigerator 12 hours or overnight. Cover and reserve remaining marinade in refrigerator.
Remove steak from marinade; discard marinade. Place steak in center of grid over medium, ash-covered coals. Grill steak, covered, 16 to 21 minutes (over medium heat on preheated gas grill, 11 to 16 minutes) for medium rare (145°F) to medium (160°F) doneness, turning occasionally.
Meanwhile, arrange peaches, tomatoes and lettuce on grid around steak. Grill peaches 2 to 4 minutes, tomatoes 2 to 3 minutes and lettuce hearts 1 to 2 minutes turning once.
Carve steak across the grain into slices. Cut lettuce into small pieces. Combine lettuce and reserved marinade in large bowl; toss to coat. Divide lettuce evenly among 4 serving plates. Arrange beef slices, peaches and tomatoes over lettuce.
Nutrition information per serving: 326 Calories; 144 kcal Calories from fat; 16 g Total Fat; 4 g Saturated Fat; 9 g Monounsaturated Fat; 66 mg Cholesterol; 446 mg Sodium; 23 g Total Carbohydrate; 2.2 g Dietary Fiber; 25 g Protein; 2 mg Iron; 7.1 mg Niacin; 0.6 mg Vitamin B6; 1.4 mcg Vitamin B12; 4.4 mg Zinc; 27.3 mcg Selenium; 94.8 mg Choline;