Preheat the oven to 350 degrees.
Pat the mahi mahi fillets dry with paper towels to remove any excess moisture.
Spray a few sprays of olive oil on both sides and rub on the fish.
Squeeze the juice from half a lime onto the fish.
Season both sides of the fish with the lime zest, coriander, sea salt, fresh black pepper and a dusting of cayenne pepper.
Place the seasoned mahi mahi in a glass baking dish or a prepared baking sheet lined with parchment paper.
Before baking, make the balsamic reduction glaze (see below).
Spoon one tablespoon on each mahi mahi fillet before baking. Reserve the other 2 tablespoons to drizzle on top of the baked fish fillets when plating.
Bake at 350 degrees for approximately 15 minutes. Cook times depend on the thickness of the fillets so double check the fish around 10-12 minutes. A great rule of thumb is to cook fish for 10 minutes per inch of thickness. My mahi mahi fillets were approximately 1.5 inches thick. When it's done, the fish will be opaque and flake easily with a fork. Cook to an internal temperature of 137 degrees.
Place mahi mahi on a serving plate, drizzle with the remaining balsamic glaze, sprinkle the fresh cilantro on top of the fillets, and top with the fresh mango salsa.