Rinse the chicken and beans thoroughly.
Cut the chicken into bite-size pieces.
Finely chop the onion and garlic.
Heat cooking oil in a pan and stir-fry the chicken.
When the chicken is halfway cooked, add the onion and garlic and continue stir-frying together.
Add the beans and stir-fry while mixing.
Season with gochujang, soy sauce, sugar, and pepper.
Continue stir-frying on medium heat until the seasonings are well absorbed and complete.