Make a slit on both sides of the chicken wings. Season with salt and pepper. Dredge in cornstarch. Shake off excess starch.
In a frying pan, pour in 2-3 cm salad oil and wait until temperature is ready for frying (185-190 degrees centigrade ). Place the wings skin side down, turning over once in a while for 6 minutes. Turn the heat up and fry another 2 minutes. Set aside and drain oil on a wire rack. Continue frying the next batch. Make sure not to over crowd them.
After all the wings have been fried, discard frying oil and clean excess oil with a kitchen paper towel. Pour the Sweet and Spicy Sauce mixture. Mix well in medium fire. When bubbles appear, immerse half batch of the chicken wings in the sauce. Make sure the wings have absorbed the sauce. Set aside on a vat and continue with the last batch of wings.