In a medium-sized bowl, mix together onion and vinegar, set aside while preparing the rest of the ingredients. Ad the tomatoes, oil, and parsley. Mix, and add salt and pepper to taste.
Best if made 24 hours in advance and refrigerated. Set out to come to room temperature one hour before serving. If making same day, give it as much time as possible.
Keywords: Brazilian, Salad, Salsa, Tomatoes, Vinegar