Combine tomatoes, olives, basil, red onion, vinegar and 2 tablespoons olive oil in a small mixing bowl. Place steaks on grill over medium heat. Grill uncovered to desired doneness g once. Place on cutting board and allow to rest 5 minutes. Slice thinly across the grain. Slice bread in half lengthwise, brush bread with remaining olive oil and grill until surface is crisp and golden, about 2 to 3 minutes. Remove bread and sprinkle with salt. To assemble, place steak on bread and top with tomato-olive salsa.
Serving option: Slice bread into 1/2-inch thick slices, top with greens, steak, and salsa for appetizers.