Whisk eggs, soy sauce, and sugar together in a large bowl.

Combine cornstarch, flour, sesame seeds, and salt in a separate bowl. Whisk in egg mixture. Fold green onions and garlic into the batter.

Stir chicken into the batter until each piece is coated. Cover and marinate in the refrigerator, 8 hours to 2 days. Stir 1 to 2 times per day.

Fill a heavy saucepan with 1 1/2 to 2 inches of oil. Heat on medium-high heat until a small amount of batter sizzles when dropped in.

Stir chicken again to coat evenly with batter. Fry in batches until deeply browned, about 3 minutes per batch. Drain on a large plate lined with paper towels or newspapers.