Place A Layer Of Sliced Tomatoes On A Large Serving Platter. Arrange The Slivers Of Red Onions And The Chunks Of Avocado Over The Tomatoes. Sprinkle With Parsley, Garlic, And Oregano. Drizzle Red Wine Vinegar And Olive Oil Over The Platter. Sprinkle With Salt And Freshly Ground Black Pepper. Serve Immediately. Do Not Refrigerate.