In a medium pot, combine the lemon juice, sugar, vinegar, soy sauce, ginger powder, garlic powder, and red pepper flakes. Heat over medium heat for about 3 minutes, stirring occasionally.

In a small bowl, mix 1 tablespoon of cornstarch with 2 tablespoons of water to create a paste. Add this paste to the lemon sauce and whisk well. Continue to cook for an additional 5 minutes, or until the sauce thickens.

In a shallow dish or pie plate, mix the flour, cornstarch, and a pinch of salt. In another shallow dish, whisk the eggs.

Dip each piece of chicken into the egg mixture, then coat it with the flour mixture. Place the coated chicken pieces on a plate.

In a heavy-bottomed pot, heat 2-3 inches of oil over medium-high heat until it reaches 350°F (175°C).

Working in batches, carefully add several chicken pieces to the hot oil. Fry for 2-3 minutes, turning often, until golden brown.

Toss the fried chicken pieces in the lemon sauce until well coated. Serve with a sprinkle of green onion and additional lemon zest for garnish.