Preheat broiler to high. Line a baking sheet with aluminum foil.
In a large bowl, stir together mango, red onion, cilantro, red pepper flakes, 3 tablespoons lime juice, and 1 tablespoon olive oil. Season with salt and pepper.
Arrange snapper, skin-side up, on baking sheet and season with salt. Drizzle with remaining 2 tablespoons olive oil and broil until skin is crispy and flesh is tender and flaky, about 8 minutes. Squeeze with remaining 1 tablespoon lime juice.
Cut snapper into 4 pieces and serve with mango salsa. Garnish with additional cilantro and lime.
The flavor pops! This island style recipe is a really good way to prepare red snapper. I found this recipe on Delish and slightly modified it here.