First, pat 1 ½ lbs boneless skinless chicken thighs dry with paper towel, then chop it into 1-inch pieces.
In a small bowl mix together 1 tablespoon cornstarch and ¼ cup water until cornstarch dissolves.
Add ⅓ cup soy sauce, 1 tablespoon rice vinegar, 3 minced garlic cloves, 1 teaspoon ginger powder, ¼ teaspoon red pepper flakes, 3 tablespoon honey, 1 teaspoon sesame oil and the liquid cornstarch mixture to a medium bowl. Stir until everything is combined and set aside.
Heat 1 tablespoon olive oil in a large pan over medium heat, then add the chicken. Cook it for about 6-8 minutes, stirring occasionally, until it’s golden brown and cooked through.
Pour the teriyaki sauce over the cooked chicken, stirring to coat. Let it simmer for about 3-4 minutes, until the sauce thickens up. Sprinkle the chicken with sesame seeds and chopped green onion (scallions) just before serving.