In a large bowl, combine the marinade ingredients. Add in the chicken and make sure every piece is well coated. Set aside for 30 minutes
In another bowl, mix all the sauce ingredients and set aside ready for cooking
Once the chicken has been marinated for at last 30 minutes, put 2 cups of cornstarch in a shallow plate along with pinch of salt and pepper, stir to combine. Set aside. Preheat oil in a small to medium deep pot until 350 F. While the oil is heating, coat every piece of the chicken in the corn starch mixture. When the oil is ready, place piece by piece of the chicken into the oil and fry until golden brown and cooked through. You can pick one out after about 5 minutes to check the inside to make sure it's no longer pink or bloody. Remove the fried chicken pieces with slotted spoon and place on absorbent kitchen towel and continue to fried the rest of the pieces
Once you've fried all the chicken, turn off the heat and remove all the little bits and pieces from the frying you did earlier. Pour off the oil until you have about 1 Tbsp left. Turn on the flame and heat the oil until really hot. Toss in the dried red chilis and stir-fry for about 10 seconds and then add in the garlic and stir-fry for another 10 seconds. Add in the sauce ingredients and cook until the sauce started to thicken
Add in the fried chicken and mix the sauce with the chicken to make sure they are coated with the sauce. Sprinkle with the spring onions. Transfer the chicken to a serving platter. Serve immediately with rice and other dishes