Apply shio koji to the entire surface of the chicken thigh, put the chicken in a ziplock bag together with cut green onion, and let it sit overnight.
After the chicken is marinated overnight, heat a frying pan over low heat, add salad oil and fry.
Wipe off excess shio koji from the chicken thighs with kitchen paper. Koji is very easy to char, so make sure to scrape off all remaining shio koji from the surface.
Put the chicken on the frying pan with the skin down, and cook both sides for 5 minutes each.
Turn off the frying pan, cover and let the chicken rest for about 5 minutes.
Cook the chicken again once more on low heat for 2 minutes.
Cut the chicken into bite-sized pieces, and serve it.