Start by cutting boneless, skinless chicken thighs into bite-sized pieces. Pat the pieces dry with a paper towel to eliminate excess moisture. In a bowl, combine cornstarch, salt, and pepper, then coat the chicken thoroughly in this mixture.

In a deep frying pan or wok, heat vegetable oil over medium-high heat until shimmering, about 350°F (175°C). Carefully drop in a small piece of chicken to test if the oil is ready; it should sizzle upon contact.

Fry the chicken pieces in batches to avoid overcrowding, cooking for about 5-7 minutes until golden brown and crispy. Drain the fried chicken on paper towels.

In a separate pan, combine freshly squeezed orange juice, soy sauce, sugar, rice vinegar, sesame oil, minced garlic, and grated ginger. Stir and bring to a gentle simmer over medium heat. Allow the sauce to thicken for about 5 minutes, stirring occasionally.

Once the sauce has thickened, add the crispy fried chicken to the pan. Gently toss the chicken in the sauce, ensuring each piece is coated evenly. Cook for an additional 2-3 minutes to allow the flavors to meld.