In a 4 to 5 quart pan, bring 2 quarts water to a boil over high heat.
Add corn and cook until tender (about 5 minutes).
Drain, rinse with cold water, until cool, and drain again.
In a salad bowl, stir together corn, beans, tomatoes, cilantro and onion.
Whisk together the ingredients of the CUMIN DRESSING.
Pour over vegetables and toss well.