Marinade chicken with soy sauce, Szechuan pepper, and salt for 20 minutes.
Combine all sauce ingredients in a small bowl.
Heat up wok or large fry pan. Add 2 tablespoon of vegetable oil. Place chicken thighs in a single layer in the pan. Fry 3 to 4 minutes on each side until golden brown and cook through.
Remove and arrange on a plate. When cool enough to handle, slice into ½-inch strips, if desired. Cover with aluminum foil to keep it warm.
Heat the remaining 1 tablespoon vegetable oil in the same wok or in a small saucepan. Sauté mince garlic for 20 seconds. Pour in sauce mixture. The sauce will become thick and bubbly very quickly.
Stir in sliced kumquats and immediately turn off heat. Add sesame oil.
Pour sauce over cooked chicken. Sprinkle sesame seeds and sliced green onions on the top.
Serve immediately with steamed rice.
Notes
*You can also use 20 oz/560g boneless skinless chicken thighs, if preferred.