Step 1

1 In a small bowl, combine the onion with 2 tablespoons of the vinegar and let sit for at least 10 and up to 30 minutes; this will mellow the onion's bite

Step 2

2 Meanwhile, in a small bowl, whisk together the oil, lemon juice and the remaining 2 tablespoons of vinegar until combined

Step 3

3 Season to taste with salt and pepper

Step 4

4 Taste, and, if desired, adjust the amounts of vinegar, juice and/or oil

Step 5

5 Drain the onions; discarding vinegar or reserving it for another use

Step 6

6 In a large, shallow bowl, gently toss together the onion, tomatoes, cucumber, bell pepper and parsley

Step 7

7 Drizzle with as much of the vinaigrette as desired, and toss gently to coat

Step 8

8 Serve immediately or let rest at room temperature for up to 30 minutes