Wash, trim, and cut green beans into 2 inch lengths.
Peel and slice garlic and shallot thinly.
Prepare stir fry sauce by mixing 3 tablespoons of oyster sauce, 1 tablespoon of light soy sauce, 1/2 tablespoon sugar, and 1/2 tablespoon sesame oil. Set aside.
Add water to a large sauce pan or deep frying pan. Fill pan about 3/4 full with water and bring to a boil. Once water is boiling, add in green beans. and boil for about 5 minutes. When green beans are tender but still crispy, set aside 3 tablespoons of leftover green bean water then drain. Take green beans out of pan and set them aside.
In the same pan, add 2 tablespoons of cooking oil. Using medium heat, add in sliced garlic and shallot into hot oil. Stir fry for about 1-2 minutes or until soft and fragrant. Turn down heat if garlic and shallots begin to burn.
Add in green beans to the pan. Add in prepared stir fry sauce and 3 tablespoons of leftover green bean water that was set aside earlier. Turn heat high. Mix everything together until sauce has evenly coated string beans. Stir fry for another 1-2 minutes or until desired green bean tenderness. Serve as a side dish or on top of a bowl of rice as a vegetable bowl.