1. Bring a large saucepan filled two-thirds with water to a boil; add beans. Cook beans until just tender, about 7 minutes. Drain in colander under cold running water.
2. Meanwhile, combine vinegar, oil, ginger, salt, sugar and lemon peel in a large bowl. Add beans, green onions and 1/4 cup of the cashews; toss well and transfer to a serving bowl. Sprinkle top with remaining 1/4 cup cashews. Serve immediately.