Most types of fish present difficulties when grilled. The flesh of smaller fish fillets is delicate and flaky and will most likely not hold up well directly on the grill. However, more meaty cuts such as swordfish, grouper and tuna, among others, are ideal for grilling. Tuna steaks grill particularly well because the flesh is firm, dense and meaty and won't fall apart on the grill. In addition, when cooked rare, the steak will remain moist and juicy.
Scrape and lightly oil the grill. Take the grill brush and scrape the grill to clean any burnt food remnants. Use a paper towel or bar towel and lightly dab with olive oil. Rub the towel over the grill to provide a light coating of oil. Be careful not to apply too much because excess oil could catch fire.
Preheat the grill. Depending on what type of grill you are using, allow ample time for the grill to preheat. For a charcoal grill, the coals usually need to burn for 20 to 30 minutes, or until most charcoal briquettes are gray in color. If you're using a gas grill, prepare the grill for direct high heat, around 400 degrees.
While the grill is preheating, prepare the tuna steaks with desired seasoning. A light coating of olive oil and a sprinkle of salt and pepper on each side of the steak should be the foundation of seasoning for the tuna. The rest depends on personal preference. See below for additional tips.
Cook the tuna. Once the raw tuna steaks are seasoned appropriately, place them on the preheated grill. Tuna steaks are often served rare, and to achieve this, they do not need much time on a hot grill. For a one-inch-thick tuna steak, three minutes on each side cooks the steak all around the edges, but leaves the inside pink and rare. Remember to close the lid once the tuna is placed on the grill. After the steaks cook for three minutes on one side, take the metal spatula and carefully flip the tuna, cooking it for an additional three minutes.
The tuna will continue to cook once removed from the grill, so it is important to have the rest of the meal planned and prepared, since the tuna does not take long to cook. Serve immediately and enjoy.