Add the chicken pieces, green onion, slices of ginger, Sichuan peppercorns, and bay leaf into a large pot. Add water, just enough to cover the chicken. Bring to a boil and then lower the heat to medium and cover the pot and let them gently simmer for 10 minutes
After 10 minutes, turn off the heat and leave the chicken pieces in the pot, covered, for about 6-8 minutes.
Prepare a large bowl of ice-cold water with some ice cubes and keep this cold in the fridge
After 6-8 minutes, use a chopstick to poke the thickest part of the chicken to see if any blood oozing out. If the juice run clear, then the chicken is done poaching. If it's still bloody, let the chicken sit for another 5 minutes or so
Soak poached chicken in ice-cold water:
Remove the chicken pieces and put in the ice-cold water and let them soak for 10 minutes. This stops the cooking process and also produce a smooth tender meat
Slice or shred the chicken:
After 10 minutes, remove from ice-cold water. You can keep the chicken skin and remove the bone and slice the meat into slices
I choose to remove the skin and shred the chicken meat instead
Prepare the sauce:
Combine ingredients for the sauce in a bowl. Have a taste and adjust to your preference. It should be spicy, numbing, and savory
Assembling:
If you shred the chicken meat like I did, toss the shredded meat in the sauce so they are well-coated. Transfer to a serving plate
If you slice the chicken meat, transfer the meat slices to a serving plate and pour the sauce over it. Use a spoon to scoop some of the sauce to make sure the chicken pieces are coated with it
Add the toppings and garnish with a few sprigs of cilantro leaves. Serve at room temperature or serve chilled