Whisk water, soy sauce, cornstarch and hot sauce to taste in a small bowl.
Heat oil in a wok or large skillet over medium-high heat. Add beans, balsamic, garlic and Olive Oil; cook, stirring, until fragrant, about 1 minute. Add the sauce mixture; cook, stirring frequently, until the beans are tender-crisp and coated with sauce, 4 to 6 minutes. Sprinkle with sesame seeds.