Sweet Corn and Black Bean Salad

1 red onion, small slices
2 cups corn kernels, fresh or frozen
1 can cooked black beans, rinsed well
1 large red bell pepper, chopped
1 cup fresh cilantro, chiffonade (divided)

Whisk together some balsamic vinegar with fresh lemon juice, salt & pepper, cumin, chili powder, and cayenne pepper to taste. Immerse the chopped onion in the dressing for about 10 minutes to release some of its sharp, acidic flavor. Blanch the corn, then combine with the rest of the ingredients. Cover and refrigerate for about 2 hours. Add the remaining cilantro and toss again before serving.