Prep: 1. Remove skin from tuna and score flesh with knife, making steaks. Repeat on all sides, but do not cut all way through. 2. Mix soy sauce, olive oil, old bay seasoning, and red pepper flakes in bowl. Brush mixture on all sides of tuna, making sure to get some marinade inside scored parts of fish. Marinate at room temperature for 15-20 min. 3. Slice tomato. Make: 1. Preheat grill to high. Make sure grates are clean and well oiled. 2. Put tuna directly on grill and cook for about 2-3 minutes on each side, or 6 minutes total for rare. 3. During last minute of cooking, toast buns on grill. 4. Slice tuna into four sections along score lines. Serve on buns with sliced tomato, arugula, and tartar sauce.
Check out our tips for buying and cooking fish here - http://blog.gatheredtable.com/2015/06/21/a-beginners-guide-to-how-to-buy-and-cook-fish/ Looking for a good substitute? Many fish types are extremely versatile, check out our recommended substitutions here - http://blog.gatheredtable.com/2015/06/21/recipe-hacking-how-to-substitute-different-types-of-fish/