Cut tomatoes in bite size pieces (grape tomatoes cut in half) and put into a bowl along with the diced red onion, if using. In a separate small bowl whisk together the Sicilian Lemon White Balsamic, your favorite Olive Tap Extra Virgin Olive Oil, basil, salt, and pepper. Pour over tomatoes (and onions) and gently toss. Top with feta cheese crumbles and gently toss again to coat.