Place onion, bell pepper, cilantro, and jalapeño peppers into a food processor. Pulse until finely chopped. Add tomatoes; pulse a few times until tomatoes are coarsely chopped. Transfer to a bowl with a tight-fitting lid.
Whisk together olive oil, red wine vinegar, lime juice, and salt in a small bowl until dressing is well combined.
Pour dressing over tomato mixture; stir well. Cover and refrigerate for at least 1 hour before serving.