Toss chicken with cornstarch.
In a small bowl mix soy sauce, sweet chili sauce, sugar and vinegar and set aside.
Heat oils in a large sized frying pan or wok.
Add chicken and cook over medium-high heat until all sides are browned.
Add mushrooms and zucchini to the chicken and cook until veggies have browned.
Stir in garlic and ginger and cook for about 2-3 more minutes.
Pour in the soy sauce mix and coat the veggies and chicken. Sprinkle sesame seeds.
Serve over some rice.