In a medium bowl, add soy sauce, rice wine vinegar, cornstarch, 1 stalk of chopped green onions, and ginger slices. Mix well.
Add in the chicken pieces, and toss several times to coat. Cover and marinate for 10-15 minutes.
Set aside a paper-towel lined plate.
Place a large pot over medium-high heat. Add in about 2-inch (5cm) oil.
When the oil is heated to about 350˚F (177˚C), use kitchen tongs to take the chicken pieces from the batter and add to the oil. Fry the chicken for about 3-5 minutes until browned and crispy. (Don’t overcrowd the pot. Fry in batches if needed.)
Using a slotted spoon, remove chicken to a prepared plate.
Add oil in a wok/pan with medium heat.
Toast Szechuan peppercorn and dried red chilies in hot oil. Fry until fragrant, about 1 minute.
Add in garlic, ginger and the remaining green onions. Stir fry for about 1 minute.
Add in the cooked chicken, salt and sugar.
Toss until combined and remove from heat.
Garnish with optional green onions or sesame seeds. Serve with rice or noodles and enjoy! (avoid biting into whole Szechuan peppercorn as they are for flavoring only)