In a large mixing bowl combine chicken cubes, salt, pepper, soy sauce (or Tamari), dry sherry, sugar, and cornstarch; toss to combine, cover, and set aside for 20 to 30 minutes.
In a separate mixing bowl whisk together soy sauce, sherry, vinegar, chicken broth, hot chili sauce, sugar, and cornstarch. Set aside.
Heat 1 tablespoon vegetable oil in a large pan or wok over medium-high heat.
Add chicken to the hot oil in one single layer; cook on all sides until done, about 4 to 5 minutes.
Remove chicken from pan/wok and return pan to heat.
Add remaining vegetable oil to the pan and heat over high heat.
Stir in peppers and sugar snap peas; cook for 2 to 3 minutes, or until just tender.
Stir in minced garlic and ginger; cook for 30 seconds.
Add chicken back into the pan and toss to combine.
Stir previously prepared sauce and then pour it over the chicken; toss to coat all ingredients.
Cook and toss for another minute or two, or until sauce thickens.
Remove from heat.
Drizzle with sesame oil.