Should it be this easy?! You don't even need a cutting board! This can be made in a jiffy while you're doing something else.
This recipe was born when I was trying to make one more dish with items I usually have on hand.
Use the canned tuna, oil and all. If you rip apart the tofu and green onions with your hands, you don't even need a kitchen knife.
Enjoy Japanese food around the world.