In a shallow baking dish combine the olive oil, orange zest, orange juice, salt, pepper and chilli flakes. Rinse the fish fillets and pat them dry. Place them into the baking dish and turn to coat with the seasonings.
Bake for 10 to 12 minutes in the preheated oven until fish can be flaked with a fork.
While the fish cooks combine the mango, onion, avocado, tomatoes, lime zest and juice, fresh chilli, ginger, coriander and 1 teaspoon kosher salt in a glass bowl. Stir to blend and set aside at room temperature until fish has finished cooking. Place fillets on a platter and spoon the salsa over them to serve.