To make the salsa, combine chopped mangoes, red onion, cucumber and mint in a bowl. Mix together gently. Add the lime juice and season to taste. Set aside in the fridge.
Lightly coat the barramundi fillets with olive oil. Season each fillet with salt and freshly ground black pepper.
Heat the grill to medium-high heat. To avoid sticking, use a pastry brush to coat the grill with olive oil. Place the fillets on the grill and cook for 3-4 minutes per side, being careful not to overcook (the edges of the fish will be bright white once ready).
Serve your grilled barramundi by placing a single fillet on each plate, with the mango salsa on top or on the side. Garnish with a sprinkle of coriander and serve with your mum’s favourite white wine.