Marinate the chicken for at least an hour
Mix the batter ingredients in a bowl. Add water a tablespoon at a time to get a thick but dippable batter. It should coat the back of a spoon.
Heat oil to 350°F
Dip marinated chicken into the batter and fry until golden and crispy, about 5 minutes per batch. Drain on a wire rack or paper towels.
Combine sauce ingredients in a bowl
Heat the wok or pan on medium-high heat
Add sauce and bring it to a simmer
When it starts to bubble, turn the heat off and stir in the cornstarch slurry
Toss the fried chicken in the sauce
Serve immediately over rice