Clean and trim the chicken, then cut it into bite-sized pieces.
Prepare the onion and sesame seeds; slice the onion thinly.
Heat oil in a pan and stir-fry the chicken first.
Once the chicken is cooked, add the sliced onions and stir-fry together.
Add the sesame seeds, stir-fry once more, then season with soy sauce.
Transfer to a plate and serve.