Black Bean, Corn, and Red Pepper Salad

2 (15 ounce) cans black beans, rinsed and drained
3 ears fresh cooked corn, kernels cut off the cob (about 2 cups)
2 red bell peppers, diced (about 2 cups)
2 medium cloves garlic, minced (about 2 teaspoons)
2 tablespoons minced shallots, from one medium shallot
2 teaspoons salt
1/4 teaspoon cayenne pepper
2 tablespoons sugar
1/2 cup plus 1 tablespoon extra virgin olive oil
1 teaspoon zest and 6 tablespoons juice from 5 to 6 limes
1/2 cup chopped fresh cilantro leaves, plus more for garnish
2 Hass avocados, chopped

Combine all ingredients except for avocados in a large bowl and mix well. Cover and chill at least 30 minutes and up to over night. Right before serving, add avocados and fold gently, being careful not to mash avocados. Garnish with more chopped cilantro if desired. Serve at room temperature.