Step 1Cut the tomatoes in half and combine them in a mixing bowl with the salt, garlic, capers, olive oil and red wine vinegar. Set aside to macerate 30 minutes, stirring occasionally. Place the red onion in a small bowl of ice water.
Step 2When ready to serve, rinse and drain the beans. Drain the red onion. Stir the beans, onion and most of the parsley into the tomatoes. Taste and adjust seasoning (it may need more salt or vinegar), garnish with the remaining parsley and serve.