Cut chicken into cubes and season with garlic salt and black pepper.
Dredge chicken cubes in flour and place on wire rack.
In a medium saucepan combine soy sauce, vinegar, sesame oil, hoisin, garlic, Asian chili sauce, ginger, and sugar. Bring to a boil over medium heat. Reduce heat to low and simmer 10 minutes.
Heat the olive oil in a skillet over medium-high heat. Cook chicken cubes in hot oil for a few minutes per side, until golden brown. Remove chicken from skillet and drain any excess oil. Add chicken back to skillet with the sauce from the saucepan.
Make a slurry from the cornstarch and water and add to the skillet. Cook over low heat for 5-6 minutes to allow the sauce to thicken.Stir sauce to ensure that it doesn’t stick. Using a rubber spatula is good for this task.
If you would like to add stir-fry veggies such as broccoli florets, bell peppers, mushrooms, snap peas, or carrots, add them to the skillet after you've sauteed the chicken and cook until tender.
To add a little extra spice you can throw in a pinch or two of red pepper flakes or Szechuan chili flakes.
Serve General Tso chicken over a bed of rice with an optional garnish of sesame seeds and sliced green onions.