Easy General Tso's Chicken

Name: Easy General Tso's Chicken
Prep time: 15 min
Cook time: 15 min
Total time: 30 min
Cuisine: Asian
Ingredients: 1/3 cup cornstarch; 1/3 cup all-purpose flour; 2 1/2 pounds boneless, skinless chicken thighs, cut into 1-inch pieces; Vegetable oil, for frying; 1 Tablespoon cornstarch; 1/4 cup soy sauce; 2 Tablespoons vegetable oil; 1/4 cup dried whole chilies, such as chile de árbol; 1 Tablespoon minced garlic; 1 Tablespoon minced ginger; 1/4 cup rice wine vinegar; 1/4 cup hoisin sauce; 1/4 cup packed light brown sugar; 1 cup chicken stock; 1 Tablespoon sesame oil; Sliced scallions, for garnishing