1Heat coals or gas grill for direct heat. To make dressing, in small bowl, stir margarita mix, oil and vinegar with wire whisk until well blended. Measure 1/4 cup dressing for basting chicken; reserve remaining dressing for serving.
2Cover and grill chicken over medium heat 15 to 20 minutes, turning and brushing occasionally with 1/4 cup dressing, until juice of chicken is no longer pink when centers of thickest pieces are cut.
3Cut chicken into slices. In large bowl, toss salad greens, chicken and strawberries; divide among 4 plates. Arrange mango and avocado around each salad. Sprinkle with cilantro. Drizzle with reserved dressing.