Step 1: Start by cutting the boneless chicken thighs or breasts into uniform bite-sized pieces, ensuring they cook evenly. Pat the chicken dry with paper towels.

Step 2: In a separate bowl, whisk together the cornstarch and all-purpose flour until well combined. Coat each piece of chicken evenly in the flour mixture.

Step 3: In a deep pan, add enough oil for deep frying and heat it to 350°F (175°C). Test if the oil is ready by dropping a small piece of the coating into it.

Step 4: Add the coated chicken pieces to the hot oil in small batches, frying for about 4 to 5 minutes until golden brown.

Step 5: In a clean pan, heat a tablespoon of oil and sauté minced garlic and sliced chilies for 1 to 2 minutes until fragrant.

Step 6: Transfer the hot fried chicken back into the pan with the sautéed garlic and chilies. Sprinkle in salt, ground white pepper, and sugar. Toss to coat.

Step 7: Serve the chicken immediately on a platter garnished with chopped green onions.