Set a grill to 350F.
Chop the tuna steak into cubes and place all the ingredients for the patties into a food processor. Pulse blend until there is a consistent texture of ground tuna.
Form patties of equal size, then place them in the refrigerator for at least 15 minutes so they can become more firm.
Place the patties on the grill and cook them for about 6 to 8 minutes, flipping halfway through. Look for the pink areas of the tuna to turn white; however, provided the tuna is fresh and good quality, you can leave some parts of the tuna pink (raw). Note: You can also cook the patties in a non-stick skillet on medium high heat if you do not want to (or cannot) cook them on a grill.
Once the patties have finished cooking, serve and enjoy immediately.