Cook the millet in 3 cups of water until all the water is absorbed, 30-45 minutes. Fluff
with a fork and allow to cool slightly. In a very large bowl, combine millet, black beans, tomatoes,
and onion. Peel the cucumber and cut into small chunks, and add it to the salad.
Mix the dressing ingredients until well-blended. Pour over the salad and toss to blend. Cover and refrigerate until the salad is well-chilled. Serve on lettuce leaves or in pita bread.