Cut the onion, pork, zucchini, and green onion into bite-sized pieces.
Heat cooking oil in a pan and stir-fry the green onion to make scallion oil.
Add the pork and stir-fry, then add the onion and zucchini and stir-fry together.
Add black bean paste and sugar, and stir-fry while mixing well with the other ingredients.
Add water and soy sauce, and bring to a boil.
Add potato starch water and adjust the thickness.