In a medium bowl mix the soy sauce with corn starch, then add chicken pieces and set aside until needed.
Prepare the vegetables by chopping up the onion, peeling and grating ginger, trimming the green beans and mincing the garlic.
In another medium bowl mix together the peanut butter, brown sugar, Chinese cooking wine, soy sauce, dried chilli flakes and hot water and whisk together till smooth. Set aside till needed.
To a large frying pan or a wok add 1/2 cup of water and bring to a boil, then add the green beans and cook for 5 minutes until tender and bright green. Remove from the wok to a separate place, discard the water and wipe the wok dry.
Put it back on the stove and heat with 1 tbsp of vegetable oil. Once the oil is hot, add the chicken pieces and cook until browned on both sides for approximately 5 minutes. Remove to the same plate as the beans.
Now add another tablespoon of vegetable oil and bring in the chopped onions to the pan, cook for 5 minutes, then add the grated ginger and minced garlic and stir fry for 30 seconds longer.
Now pour the pre-mixed peanut sauce into the hot pan and bring to a simmer. Add the chicken and green beans and simmer over 5 medium heat for 5 minutes until the sauce is thick and glossy. If the sauce is too thick, add a splash of water.
Serve sprinkled with sliced green onions and sesame seeds.