1. In a small bowl, blend together the chicken broth, soy sauce, rice vinegar, barbecue sauce, and sugar. In a separate bowl, combine the cornstarch and water and stir to dissolve.

2. Heat the oil in a wok or large skillet. Add the beans and toss to coat evenly. Add the onions, garlic, and ginger and stir over high heat for 30 seconds. Pour on the chicken broth mixture and reduce the heat. Cover the pan and simmer for 2 to 3 minutes. When the beans are crisp-tender, pour on the dissolved cornstarch. Increase the heat and stir until the sauce is slightly thickened. Serve at once.