First, debone the chicken thighs by cutting along the bone with scissors.

Cut off and discard the cartilage.

Cut the chicken thigh meat into large pieces.

Marinate the chicken with 2 tablespoons of light soy sauce, 1/2 tablespoon of dark soy sauce, 1 tablespoon of oyster sauce, 1 tablespoon of cornstarch, and some black pepper. Mix well and let it marinate.

Slice the lemon and remove the seeds. Cut the onion into small pieces.

Heat oil in a pan and add the chicken thighs. Pan-fry on medium heat until both sides are golden brown. 

Add the onion and garlic, and stir-fry until fragrant.

Add the sliced lemon, cilantro, and small hot chili peppers. Add 1/2 tablespoon of sugar (optional).

Stir-fry for 1-2 minutes until well mixed, then it's ready to serve.