Rinse, drain, and pat dry the green beans. Trim the end off of each green bean.
Heat the oil in a 12-inch skillet over medium-high heat until just smoking. Add the green beans and 1/8 teaspoon of salt and shake the green beans into an even layer. Cook the green beans, stirring occasionally, until spotty brown, about 2-3 minutes.
Reduce the heat to medium, and add the water, cover, and cook the green beans until they are bright green but still crisp about 2-3 minutes.
Uncover the pan, add the butter, and increase the heat to high, and continue to cook until the water evaporates and the beans are crisp-tender, about 1-2 minutes longer.
Season the beans with salt and pepper, and then serve.