Trim green beans and steam until tender, about 10 minutes.
Stir Fry
In a small bowl, combine the soy sauce, Hoisin sauce, vinegar, sesame oil, cornstarch, and Sriracha and stir until the cornstarch has dissolved.
In a large skillet, heat the oil over high heat. Add the chicken and red pepper, cook and stir until no trace of pink remains on the surface. Add the green beans, then garlic and ginger. Cook and stir for one minute. Add the sauce mixture and cook,stirring constantly, until mixture is thickened and the chicken is cooked through, about 2 minutes. Stir in Thai basil, if desired.