1 ½tablespoonoil (for frying - peanut oil or other high smoke point/flavorless best)
½lbyellow fin tunasushi grade ideally in a square/rectangular block
Instructions
In a small bowl, mix together the orange juice, lemon juice, soy sauce, mirin and ginger. Set aside.
If your piece of tuna is wider, cut it into two similar-sized pieces, ideally both square/rectangular ended and even width.
Warm the oil in a skillet big enough for the piece of tuna over a medium-high heat until it starts to smoke slightly.
Add the tuna to the pan and cook for no more than around 30-45 seconds each side to sear it. Remove from the pan and set aside a couple minutes.
Using a very sharp knife, cut the tuna thinly across the grain. Arrange the slices on a larger platter or two plates to serve. Drizzle over the sauce and decorate the plate, if you like eg with slices of lemon, green onions.
Notes
If you want to add a little more of a kick, you can add a pinch of red pepper flakes to the sauce. You can also add sliced jalepeños when you decorate. Typically a ponzu like this would also include dashi and/or dried bonito flakes for more umami flavor - feel free to add a small pinch.To get a little more citrus flavor, you can rest the tuna on slices of lemon rather than just to decorate the plate.