#1 In a medium bowl, stir together tomatoes, mango, yogurt, cilantro, chili sauce, and ½ teaspoon salt. Set aside. #2 Place fish on a foil-lined, rimmed baking sheet. Squeeze juice from half of the lime over top, sprinkle with remaining salt, and drizzle with olive oil. Adjust oven rack to highest position and heat broiler to high. Broil fish until it is semi-firm to light pressure and charred around the edges, 2 to 3 minutes. Remove and set aside. #3 Warm tortillas in a nonstick skillet over medium-high heat. #4 Remove skin from fish and divide fish among tortillas. Squeeze with remaining half lime, top with yogurt-mango mixture and lettuce, and serve.