Cut the zucchini into strips. Thinly slice the onion

Heat a large skillet to medium. Add the oil and stirfry the onions until they are mostly done. Add the zucchini and cook, stirring, for about 1 minute. Stir in desired amount of oyster sauce (start with 2 tsp), soy sauce, and sesame seeds and cook until the zucchini are tender, about 1 minute. Add pepper and serve.