Cut boneless chicken thighs into 1-inch bite-size pieces, pat dry, then sprinkle lightly with salt and pepper.

Whisk two large eggs in a medium bowl until frothy, then add chicken pieces and toss to coat evenly.

Dredge each chicken piece in cornstarch, turning to cover fully, then shake off excess.

Heat vegetable oil in a wok or heavy-bottomed pan to 350°F (175°C), then fry chicken in batches until golden brown and crisp, about 5–6 minutes per batch.

Combine soy sauce, rice vinegar, sugar, and chicken broth in a bowl, whisking until sugar dissolves.

Sauté minced garlic and ginger in 1 tablespoon vegetable oil until fragrant.

Add sauce mixture and dried red chili flakes to the pan, stir and simmer until sauce reduces slightly and thickens.

Toss the crispy chicken pieces into the sauce, stirring to ensure each piece is coated.

Garnish with green onions and toasted sesame seeds, if desired.