, cut into 1-in. pieces
, for frying
, cut into quarters and thinly sliced
, thinly sliced diagonally
STIR chicken, garlic, soy, sesame oil, salt and pepper in a bowl. Cover and marinate for 30 min.
POUR enough oil into a large heavy-bottomed pot to reach 1 in. up the side. Clip a deep-fry thermometer to the side. Heat over medium-high to reach 350F, adjusting heat as needed to maintain temperature. Place a wire rack over a baking sheet and set aside.
RESERVE 4 tsp cornstarch and place remainder in a bowl. Add chicken and toss until coated. Fry in batches, 8 pieces at a time, until chicken is golden, about 2 min. Drain on rack and repeat.
WHISK remaining 4 tsp cornstarch, sugar, lemon juice and broth in a large saucepan over medium-high, until sauce thickens and boils for 1 min. Stir in chicken and lemon slices until coated.
PLATE and sprinkle with sesame seeds and green onions.