Place green beans in a large pan. Add 1/3 cup of water. Bring to a simmer over medium-high heat. Cover, and cook for about 3-5 minutes, or until slightly tender but still crispy.
Remove the lid from the pan, and stir until the water is evaporated. Make a well in the center of the pan, drizzling the oil in the center.
Add the garlic and ginger to the oil, stirring until fragrant. Quickly mix in the mustard seeds, red pepper flakes, salt and pepper. Mustard seeds may pop. Cook until your desired doneness. Serve!