with Mango Sauce
6 tablespoons olive oil
5 tablespoons chopped fresh cilantro
3 tablespoons fresh lime juice
1 ½ teaspoons grated lime peel
1 large mango, peeled, cut into thick wedges
¾ teaspoon cumin seeds
8 large red-leaf lettuce leaves
Prepare barbecue (medium heat). Whisk oil, 4 tablespoons cilantro, lime juice, and lime peel in small bowl. Season vinaigrette with salt and pepper. Brush all sides of fish and mango with some of vinaigrette. Reserve remaining vinaigrette. Sprinkle fish and mango with salt, pepper, and cumin seeds. Grill fish without turning until fish is just opaque in center and mango is soft and beginning to brown, about 6 minutes.
Overlap 2 lettuce leaves on each of 4 plates. Top with fish and mango. Drizzle with remaining vinaigrette. Sprinkle with 1 tablespoon fresh cilantro.