Tuna tartare is typically served raw, as it consists of raw tuna that has been finely chopped or minced and combined with various ingredients such as mayonnaise, ginger, sesame oil and soy sauce.  However, some recipes call for lightly searing the tuna before adding the other ingredients to create a cooked version of the dish. This adds flavor while still preserving the unique texture of a classic tartare.  For safety reasons, always choose sushi-grade tuna when preparing this dish to ensure that any potential contaminants have been eliminated. If you're concerned about consuming uncooked fish, you can lightly cook the tuna in a pan over medium heat. Be sure not to overcook it so that you don't lose its delicate flavor.