Cut chicken into 1-inch chunks and pat dry with a paper towel
Whisk together 1 tablespoon dry sherry, 1 tablespoon soy sauce, 1 tablespoon sesame oil, and 1 tablespoon of cornstarch mixed with 1 tablespoon water to make a slurry. Whisk until the marinade is thoroughly combined.
Add the chicken pieces to the marinade and toss to combine. Set aside in the refrigerator for 20 to 30 minutes.
In a medium bowl, whisk together the remaining 1 tablespoon dry sherry, 3 tablespoons of soy sauce, sugar, 1 tablespoon sesame oil, rice vinegar, ginger paste, garlic paste, Sichuan peppercorns, and remaining cornstarch/water slurry.
Remove the stems and seeds from the bell peppers and discard them. Discard the white parts of the green onions.
Cut the bell peppers into 1-inch chunks and slice green onions into 1-inch sections.
Cooking The Chicken
Drain the marinating chicken and discard the liquid.
Heat 1 to 2 tablespoons of sesame oil in a large skillet over high heat. Add drained chicken and saute until browned on all sides and the meat is white and cooked all the way through. Remove chicken from the pan and set aside.
Cooking The Sauce
Add 1 more tablespoon of sesame oil to the skillet. Add the bell peppers and dried chile peppers. Saute for 1 minute.
Pour the sauce mixture into the skillet with the vegetables (peppers and onions) and cook for 1 to 2 minutes until the sauce thickens.
Add the cooked chicken, green onions, and peanuts to the pan and saute to warm all ingredients through.
The cornstarch slurry is used to thicken up the sauce.
There is some mild-medium heat and spice in this dish, mainly from the chiles and the Sichuan peppercorns. For more heat, saute the peppercorns and/or the chiles for a bit longer before adding them to the sauce.