Gōngbǎo Jīdīng (Sichuan Kung Pao Chicken)

1 1/2 pounds, boneless, skinless chicken thighs, trimmed and cut into ½-inch cubes 1/4 cup, soy sauce, divided 1 tablespoon, cornstarch 1 tablespoon, Chinese rice wine or dry sherry 1/2 teaspoon, white pepper 1 tablespoon, Chinese black vinegar 1 tablespoon, packed dark brown sugar 2 teaspoons, toasted sesame oil 1 tablespoon, minced garlic 2 teaspoons, grated fresh ginger 2 tablespoons plus 1 teaspoon, vegetable oil, divided 1/2 cup, dry-roasted peanuts 10-15 , dried arbol chiles, halved lengthwise and seeded 1 teaspoon, Sichuan peppercorns, ground coarse 2 , celery ribs, cut into ½-inch pieces 5 , scallions, white and light green parts only, cut into ½-inch pieces