Summarize the following:
Ahi tuna can refer to yellowfin or bigeye tuna, either of which makes a fine tuna steak. Albacore is generally cheaper and still a favorite of some cooks. Nowadays, frozen fillets at a fishmonger can be high quality, and much cheaper than the fresh stuff. Look for cuts that are neatly trimmed, with firm, dark red flesh. Avoid any with discolored flesh around the bone, or with a brown tinge. Thick cuts are necessary to create a seared crust without overcooking the inner flesh. Aim for a cut at least 1¼" (3.2 cm) thick. In a medium bowl, mix together the soy sauce, mirin, honey and sesame oil with a whisk. If you can't find mirin, use white wine or sherry, with a small pinch of sugar stirred in. Set aside one portion to use as a dipping sauce. Whisk until incorporated. Place the marinade and tuna in a sealable plastic bag and refrigerate. Leave it for up to 2 hours to allow the flavors to blend. Some chefs recommend keeping this to 30 minutes or less, or even just briefly rubbing in the marinade. The shorter marinade could result in more tender meat, but a more fishy flavor. Remove the tuna steaks from the bag and drain off excess marinade. Cover them in a crust of sesame seeds, pressing gently to adhere them to the surface. Use both white and black sesame seeds for an attractive presentation. Searing requires very high temperatures. If using a gas grill, bring it to 450ºF (230ºC). If using a stove, use a heavy skillet good at conducting heat, preferably a well-seasoned cast iron pan. Add peanut oil, refined (non-extra-virgin) olive oil, or another oil with a high smoking point. When the oil shimmers or just begins to smoke, the pan is hot enough for the tuna. . Sear until brown on the outside and opaque in the center, with a golden-brown sesame seed crust. This will take about 1–2 minutes on each side. Sear for just 30 seconds on each side if you prefer a rare center. Due to risk of parasites, this method should only be used for tuna that's been frozen. Remove the steaks from the skillet and serve with the reserved dipping sauce.

Summary:
Select your tuna. Start mixing the marinade. Divide the mixture into two equal portions. Add the rice wine vinegar to the marinade mixture. Marinate the tuna. Press in the sesame seeds. Heat a grill or cast iron skillet. Sear the tuna steaks Serve.