Combine all dressing ingredients in a small bowl and whisk until well blended. Cover and refrigerate until serving time.
Combine mango, jicama, red pepper, cilantro and lime juice in a medium bowl. Toss gently but thoroughly. Cover and chill. Arrange lettuce leaves on 6 salad plates. Mound 1/2 cup mango mixture in center of plate. Drizzle 1 1/2 tablespoons dressing over each salad. Garnish with onion rings.
Makes 6 servings.
Nutritional information per serving: 113 calories, 2 g protein, 19 g carbohydrate, 4 g fat, 12 mg cholesterol, 49 mg sodium