Step 1

Whisk together the olive oil, soy sauce, lemon juice, garlic, red pepper flakes, black pepper, ginger, green onion, and salt in a bowl. Add the mahi mahi and toss to evenly coat. Cover the bowl with plastic wrap, and marinate in the refrigerator for 1 hour.

Step 2

Preheat the oven's broiler and set the oven rack in the middle of the oven.

Step 3

Bring the rice, water, chicken bouillon, and 1 tablespoon butter to a boil in a saucepan over high heat. Reduce heat to medium-low, cover, and simmer until the liquid has been absorbed, about 20 minutes. Pour in the coconut milk and 2 tablespoons of sugar. Stir, and simmer uncovered until the rice has absorbed most of the coconut milk.

Step 4

While the rice is cooking, remove the mahi mahi from the marinade, and shake off excess. Discard the remaining marinade. Place fish in a large baking dish in a single layer. Broil in the preheated oven until the fish flakes easily with a fork, 10 to 15 minutes. If the fish browns too quickly, cover the baking dish with a sheet of aluminum foil.

Step 5

Melt 1 1/2 teaspoons butter and 1 1/2 tablespoons of sugar in a skillet over medium-high heat. When the mixture begins to bubble, stir in mango cubes. Cook and stir until mango is tender, about 5 minutes. Serve by placing a mahi mahi fillet over a scoop of hot rice and top with the mango salsa.