MIX THE BATTER INGREDIENTS together in a medium-sized bowl; it should be thick and smooth. Allow the batter to sit, covered for at least 30 minutes. Combine the chicken with the batter. Heat a wok or large deep skillet until it is hot and add the oil for frying. When the oil is barely smoking, deep-fry the chicken for 2 minutes or until the batter is just firm. You should do this in several batches. Remove the chicken with a slotted spoon and drain on paper towels. TO MAKE SAUCE: Heat a small saucepan; when it is hot, add the oil, ginger and garlic, and stir for 30 seconds. Then add the rest of the sauce ingredients and simmer for 2 minutes. Keep warm. Reheat the oil in the wok until it is very hot, but not smoking. Deep-fry the chicken again until it is golden and crisp, about 1 minute. Remove and drain, place on a warm platter, drizzle with the sauce and serve immediately.