Wash the tomatoes and slice them and place them in the colander. The more assortment of tomatoes (sizes and colors), the prettier the salad will be. Toss in a Tablespoon of Kosher salt and let the tomatoes sit in the colander for 20 minutes.

Transfer the tomatoes to a serving bowl and toss in the oregano.

For the dressing, mix together 1 part oil, 3 parts vinegar, and the garlic. Drizzle the dressing over the tomatoes and toss until lightly coated--but not too much. Garnish with the cheese and onion slices, if preferred.