Rinse tuna steaks and pat dry. Arrange tuna in a 13x9 inch baking dish. Mix lime juice, soy sauce, honey, chili sauce, and olive oil in a small bowl. Pour over tuna. Turn fish to coat with marinade. Cover and refrigerate for 1 to 2 hours.
Prepare grill to medium-high heat. Remove tuna from marinade. Pour remaining marinade into a small saucepan and set aside. Cook tuna over hot coals 4 to 5 minutes on each side. Fish should be lightly browned on outside and pale pink on thickest part. Remove from heat.
Bring reserved marinade to a boil over medium-high heat. Mix cornstarch with 2 tablespoons water until smooth. Add to marinade. Cook and stir until sauce thickens, about 1 minute. Spoon sauce over tuna steaks and serve immediately.
Notes
Bottled chili sauce is found near the ketchup and sauces in your local market.