In a bowl, combine soy sauce, vinegar and cornstarch.
Add to the chicken and massage to coat each chicken piece well.
In another bowl, combine both the soy sauces, vinegar, sugar and cornstarch.
Heat oil in a pan and cook the chicken over medium heat until almost done. Remove and set aside.
Add a little more oil to the same pan and sauté minced ginger and garlic along with the red chilies.
Add chicken and peanuts into the pan. Season with salt, pepper and red pepper flakes.
Pour the prepare Kung Pao sauce into the pan and turn down the heat.
Keep stirring until the sauce thickens. Taste and season again if required.
Notes
Chop the chicken into cubes that are roughly the same size. This will ensure even cooking.
Pat the chicken dry and remove all moisture before you coat it in the cornstarch and soy sauce mixture.
To bulk up the dish, you can dice veggies like mushrooms, bell peppers, carrots, zucchini and onions and add them in too. You'll need to stir fry them with the aromatics first, and also increase the amount of sauce you're using.
Turn down the heat once you add the Kung Pao sauce and keep stirring until it gets nice and thick.