Bring a large pot of lightly salted water to a boil. Place the green beans in the hot water and cook for 3 to 5 minutes, till they turn a bright green and are still crisp-tender. Drain and run cold water over them, drain again.
Meanwhile heat a large wok or skillet over medium-high heat. Add the sesame (or peanut) oil to the wok and add in the garlic and ginger, stirring for 20 seconds until fragrant. Add the onion and cook until they turn soft and nearly translucent, about 3 to 5 minutes.
Add the green beans and the remaining ingredients to the wok. Stir to combine and the sauce coats the green beans and starts to slightly caramelize the green beans, about 3 minutes. Serve hot and enjoy!