1Place onion flat sides down and thinly slice crosswise.
2Combine vinegar, water, sugar, cumin, chili powder and salt in container with lid. Shake well to mix, add onion and shake to coat onion thoroughly.
3Place in refrigerator and marinate overnight, shaking onions in marinade 2 or 3 times.
4To assemble salad, heap lettuce on 4 plates.Arrange tomato slices on salads.
5Lift onions from marinade and heap into center.
6Halve, seed and peel avocado.
7Slice each half lengthwise into thin slices, keeping slices attached at one end. Fan out and divide each fan onto two salads.
8Sprinkle salads with cilantro and chile slices. Add olives. Serve with Picante Vinaigrette.
9Picante Vinaigrette: In jar, combine 1/4 cup olive oil, 2 tablespoons red wine vinegar, 2 tablespoons medium picante sauce, 1 tablespoon sugar and 1 teaspoon dried oregano; shake well. Makes 1/2 cup dressing.