Hull strawberries and cut into 3/4-inch cubes. Place in a large bowl. Add mango, avocado, chilli, lime juice, coriander and salt. Stir gently to combine. Set aside.
Preheat grill to medium-high. Brush halibut fillets with oil and season with remaining 1/4 teaspoon salt and pepper. Grill fillets, skin side up and covered, 4 to 5 minutes, turn over gently and continue to cook 3 to 5 minutes or until fish is opaque throughout. Serve with squeeze of fresh lime juice and salsa.