I love tuna. I love wafu (Japanese style) tastes. I love sushi.
Those three things combined is this dish: marinated and quickly seared tuna!
I adapted this recipe from http://culinary.jwu.edu/content1590.html.
Buy sushi grade tuna from your grocer, I recently saw some at Trader Joes. I usually get one or two stakes, which is usually under a pound.
Create the marinade (mix in bowl):
2 tablespoons of sugar
1 teaspoon of finely minced fresh ginger
2 teaspoons of soy sauce or tamari
1/4 cup of rice wine vinegar
1 tablespoon of sesame oil
1 teaspoon of lemon juice
Let the tuna marinate for 20-40 minutes in the fridge. Unlike beef, you don't need to beat up your meat or poke it, just set it in the marinade and spoon some over the top.
Start cooking your rice, steaming your veggies, whatever-- the tuna will cook up quickly!
When you are about 5-7 minutes away from "go-time" with your side dishes, heat a pan on high heat. When the pan is hot, you can add a small dab of canola/veggie oil (not olive or butter, they will burn at high heat) and swirl it around.
Pull the tuna out of the fridge. When you take the steak(s) out of the marinade, you can optionally sprinkle wasabi powder on for a little spicy kick.
Get out your timer! With a stopwatch set for 1 minute 30 seconds, stick the tuna into the hot pan with oil-- careful, it will sizzle and spatter. When the timer goes off, use a fork to turn the steak(s) and reset your timer for another 1 minute 30 seconds. You can sear it for longer if you want your tuna well-done, but I like it a little raw in the middle (it's sushi grade :).
Promptly take the tuna out and let it rest on a plate. Now you get to use the left over marinade! Dump the marinade into the hot pan, but be VERY CAREFUL because it will spatter and sizzle and generally try to burn you. Let the marinade boil down into a thick-ish sauce, at which point you can drizzle it over the tuna and/or your veggies. YUM!