Cut the tuna into 1/4-inch slices, then cut lengthwise into strips and across into 1/4-inch dice. Place in a small bowl.

Add the ginger oil, wasabi, sesame seeds, cilantro, 1/4 teaspoon of salt, and pepper. Stir to combine, then set aside for a few minutes to let the flavors develop.

Taste and add a bit more salt if necessary.