Slice the chicken breast thinly.
Season with salt and pepper.
Mix potato starch and water to make batter.
Coat the chicken breast in the batter.
Heat oil in a pan and fry the chicken breast.
Remove excess oil from the fried chicken and set aside.
Add soy sauce, vinegar, sugar, and water to a pan to make the sauce.
Toss the chicken breast in the sauce.
Garnish with sesame seeds and green onion.