Soak whole sprouts in a large bowl of cold, salted water to clean. Then trim and discard ends and any bitter outer leaves. Cut each in half lengthwise, then slice thinly across width.
Heat the oil in a large skillet over medium high heat. saute the sprouts and onion with the cumin, salt and pepper until the sprouts start to brown. Add water and cook until barely limp, about 4 minutes. Stir in the lime juice and serve immediately.