In a small mixing bowl whisk together the soy sauce, sesame seed oil, mirin, honey, rice vinegar, and salt; remove half of the sauce/marinade and transfer it to a small serving bowl. Set it aside.
Pour the rest of the marinade into the plastic bag with the tuna.
Close the bag and massage the liquid around to coat the tuna steaks. Let stand 10 minutes. (You can also refrigerate overnight.)
In the meantime, in a small bowl combine the sesame seeds, garlic powder, salt, and pepper.
Sprinkle all sides of the tuna steaks with the sesame seeds mix, pressing down to adhere.
Heat a cast iron skillet over medium-high heat until very hot.
Add 2 tablespoons vegetable oil to the hot skillet and heat it up.
Place the tuna steaks in the hot pan, pressing them down with a metal spatula; cook for about 1 to 1-1/2 minutes for rare, or 2 minutes for medium-rare. (I suggest to cook two tuna-steaks at a time.)
Using tongs, sear the sides for about 20 to 30 seconds per side, while holding the fish with the tongs.
Transfer the tuna steaks to a cutting board and let rest for 3 minutes.
Using a sharp knife, slice and serve with the reserved sauce.
Nutritional info is an estimate and provided as courtesy. Values may vary according to the ingredients and tools used. Please use your preferred nutritional calculator for more detailed info.
Course: Main Course
Cuisine: American, Asian
Keyword: ahi tuna steak recipe, how to cook tuna steaks, seared tuna