SWEET AND SOUR CHICKEN
Cut the chicken into 1/2-inch cubes. Marinate in the vineger and cornstarch for 30 minutes.
While the chicken is marinating, prepare the vegetables: mince the garlic clove, peel and cut the cucumber into thin slices, and cut the red pepper into cubes. Chop the baby carrots. Bring a large pot of water to boil and blanch the carrots briefly in the boiling water. Drain thoroughly.
In a small saucepan, add the ingredients for the sweet and sour sauce and bring to a boil. Turn the heat to low and keep warm.
To deep-fry the chicken: While waiting for the oil to heat, brush the chicken cubes with the beaten egg and dip in the potato starch to cover. Deep-fry the dredged chicken pieces in batches, being careful not to overcrowd the wok. Deep-fry for 3 - 4 minutes until the chicken turns golden brown. Drain on paper towels.
To deep-fry the chicken a second time if desired: bring the oil temperature up to 400 degrees Fahrenheit. Deep-fry the chicken in batches, very briefly for less than a minute, until the chicken turns brown. Drain on paper towels.
Drain all but 2 tablespoons oil from the wok. When oil is hot, add the garlic and stir-fry briefly until aromatic. Add the carrots. Stir-fry for about 1 minute, then add the red peppers. Add the cucumber or save to use as a garnish.
Bring the sauce back up to a boil and add to the wok, mixing with the vegetables. Add the chicken. Heat through and serve over rice. Garnish with the cucumber if desired.