Adapted from lifetasteslikefood.com
Let tuna steak completely defrost overnight in the fridge (if using fresh tuna, skip this step). Lightly use a paper towel and pat the steak to absorbe excess juices. Cut steak to your liking–you can sear the entire steak as it is or cut it into a rectangle to get more even slices (I did the latter and cut my tuna steak in half to get smaller pieces). In a separate bowl big enough to fit the tuna steak, add the black and white sesame seeds as well as a sprinkle of kosher salt. Using tongs, coat the entire outside of the tuna by pressing it into the sesame seeds until the steak is completely covered. In a pan, add enough oil to just coat the bottom of the pan and preheat the pan to medium-high heat. Then take the tuna and place it in the hot pan and sear for about 45 seconds* on all sides (including the skinnier sides!). Tongs really help for this process. Slice steak up into pieces and serve on a bed of arugula with soy sauce and wasabi. You can also drizzle some teriyaki sauce over them for flavor if you’d like!