Add the water and immediately cover. Steam until the beans are crisp-tender, 2–3 minutes.
Uncover and push the beans to one side to clear a small space. Add the garlic to the oil in the cleared spot and cook until fragrant, 30–60 seconds, then toss to coat the beans.
Continue cooking uncovered, stirring occasionally, until the beans are tender-crisp with a few blistered spots, 2–3 minutes more. Season with black pepper and adjust salt to taste. Serve hot.