Cut the tofu into bite-sized pieces.
Drain the oil from the canned tuna and set aside.
Finely chop the onion and Cheongyang chili peppers.
Add the tuna to a pan and stir-fry over medium heat.
Add the chopped onion and chili peppers to the pan and stir-fry together.
Add ssamjang, soy sauce, and oligosaccharide syrup, and mix evenly.
Serve the stir-fried spicy tuna ssamjang on top of the tofu.