Preheat oven to 400°F. Line a baking sheet with parchment paper.
Make the salsa: In a bowl, combine diced mangoes, red bell pepper, red onion, jalapeño, cilantro, lime juice, and 1/4 tsp salt. Toss well and set aside.
Pat the mahi mahi fillets dry with paper towels. Rub both sides with olive oil.
Season the fillets with 1 tsp salt, black pepper, cumin, and chili powder.
Place the fillets on the prepared baking sheet. Bake for 12-15 minutes, until the fish is opaque and flakes easily with a fork (145°F internally).
Top each fillet with mango salsa and serve with lime wedges.