Stir the mango, tomato, cucumber, chickpeas, lime juice, lemon juice, jalapeno pepper, chilli flakes and lemon basil in a bowl; season with sea salt. Set aside.
Preheat a barbecue for high heat and lightly oil the grate.
Season the trevally with the paprika, salt and pepper; brush with the canola oil.
Cook the trevally on the preheated barbecue until the fish flakes easily with a fork, about 3 minutes per side. Quickly warm the tortillas on the barbecue just before the trevally is finished. Serve the trevally in the warm tortillas topped with the mango salsa.