1. Trim ends of radishes and cut into 1/8-inch-thick slices. Peel oranges and cut into 1/4 to 1/2-inch-thick slices. Trim green onions and cut into 1/8-inch-thick slices.

2. Place radishes, oranges, and green onions in a 1-quart bowl. Toss with lime juice, cilantro (if used), oil, vinegar, and salt. Marinate for 30 minutes. Place 1/3 cup of salad on each lettuce leaf. Serve on chilled plates.