Whisk together olive oil, lemon juice, salt and pepper in a bowl. Tear watercress into bite-sized pieces and toss with dressing. Divide salad among 6 serving plates. Thinly slice avocado halves into strips lengthwise. Garnish center of each salad with avocado and serve.
c.1997, M.S. Milliken & S. Feniger, all rights reserved