First, you'll want to marinate the onions and garlic in the dressing.  This will help diffuse their flavor and soften their bite so that you don't get a strong red onion that makes you cry or gives you instant indigestion.

In a small bowl whisk together the olive oil, red wine vinegar, Dijon mustard, minced garlic, salt, and pepper. Add the sliced red onions and let them marinate for 10 to 15 minutes while you prep the salad.

Combine the chopped tomatoes, parsley, and white beans in a large bowl.

Pour the onions and dressing over the tomatoes and white beans and toss well.  Add the shaved parmesan cheese right on top and gently fold it into the salad.

You can make this ahead of time and refrigerate or serve it at room temperature.

Be sure to have some rustic bread on hand to sop up the delicious juices when you are done eating the salad.  That's the best part!