In a large serving bowl, whisk together the red wine vinegar, grapeseed oil, cilantro, lime juice, sugar, salt and garlic. Set aside.
Bring a large pot of lightly salted water to a boil. Add the soybeans and boil for 3 minutes. Add corn to the boiling water and continue cooking for 1 more minute. Drain very well, and pour into the bowl with the dressing. Gently mix in the cherry tomatoes, green onions and black beans.
Cover and refrigerate for at least 2 hours before serving to chill and blend the flavors.
