Cut the tuna into bite-sized pieces.
Put the tuna and Ponzu Soy Sauce in a plastic bag, knead, and leave in the refrigerator for about 10 minutes.
Drain (1) and wipe off excess marinade. Lightly coat tuna with corn starch.
Preheat the oil to 340-360℉ (170-180℃). Deep fry until golden brown.
Serve on a plate with shiso.
