To a medium bowl, add the chopped tomatoes, onion, parsley, oil, vinegar, and salt and pepper. Gently toss until all ingredients are evenly dispersed and coated. Taste, and adjust salt and pepper if needed. Serve immediately and enjoy.
3 cups cherry tomatoes, 1/2 red onion, 1/2 cup fresh parsley, 1 tablespoon extra virgin olive oil, 1 tablespoon red wine vinegar, salt and pepper to taste