Great color, flavor, and taste. Prepare dressing by combining olive oil, vinegar, mustard, roasted peppers, and basil in small food processor or blender. Process until smooth. Add tabasco to taste. Combine vegetables and place in large grilling basket.
Coat vegetables lightly with olive oil spray and sprinkle with salt and pepper.
Place on grill and loosely cover basket with aluminum foil. Stir occasionally and grill until brown and tender. While vegetables are cooking, place tuna on grill. Coat lightly with olive oil spray. Grill just until done in the middle.