Preheat the grill to a high temperature if grilling. If using a gas grill, turn it on to high and close the lid to allow the grates to get extremely hot. Be sure to oil the tuna or the grill before putting it on. If using a charcoal grill, either cook it over a preheated grate on direct heat, or you can cook a tuna steak directly over a charcoal chimney. To do this, light charcoal in a chimney until the coals are burning, then place grilling grate or similar rack directly over the chimney. Again, allow the grate to preheat to help avoid sticking, and to sear most efficiently. When grilling over high heat, a total cooking time of four minutes will result in a rare tuna steak. You can cook for two minutes per side, or allow 2 1/2 minutes on one side and 1 1/2 minutes on the other. If you prefer your tuna steak more done, simply leave it on longer.
Asian flavors work very well with tuna steaks, such as teriyaki.
Sliced ginger and wasabi are often used as condiments for tuna.
Use extreme caution when handling a charcoal chimney, as they get very hot.