Step 1

In a small bowl, mix together the orange juice, lemon juice, soy sauce, mirin and ginger. Set aside.

Step 2

If your piece of tuna is wider, cut it into two similar-sized pieces, ideally both square/rectangular ended and even width.

Step 3

Warm the oil in a skillet big enough for the piece of tuna over a medium-high heat until it starts to smoke slightly.

Step 4

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.

Step 5

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.