First, make the vinaigrette: in a small bowl, whisk together the vinegar, garlic, capers, chili flakes, and oregano. Slowly whisk in the oil. Taste for seasoning. You should have enough vinaigrette for 6 servings.
For each salad serving: Lay the sliced tomatoes on a serving plate.
In a bowl, combine the tomato wedges, cherry tomatoes, peppers, beans, and a few torn basil leaves. Add about 3 tablespoons Caper-Sherry Vinaigrette and gently mix.
Arrange the tomato-bean mixture over the tomato slices. Drizzle another tablespoon of dressing over the top.
If desired, add sliced of prosciutto over the top. Garnish with a few torn basil leaves.
