Cut the zucchini and oyster mushrooms into bite-sized pieces.
Julienne the onion and green onion.
Add cooking oil to a pan and stir-fry the green onion to bring out its aroma.
Add the zucchini, oyster mushrooms, and onion, and stir-fry together.
Season with salt and pepper.
Once the vegetables have softened, add sesame oil and mix well.