Grapefruit, Mango and Sweet Onion Salad

Dressing:
2 Tablespoons fresh lime juice
¼ teaspoon salt
1⁄8 teaspoon freshly ground pepper
¼ teaspoon chili powder
1 Tablespoon minced red bell pepper
3 Tablespoons minced fresh cilantro
½ cup extra virgin olive oil

Salad:
1 small head leaf lettuce, torn
2 medium pink seedless grapefruits, segmented and cut into 1-inch pieces
1 large or 2 medium mangoes, peeled, pitted, and chopped
1 large 1015 onion, or any other sweet onion, halved and thinly sliced
¼ cup chopped fresh cilantro