In a large bowl, whisk together 1/4 cup lime juice, 1 tablespoon red wine vinegar, 1 tablespoon olive oil, 1 1/2 teaspoons salt, 1/2 teaspoon pepper, 1/4 teaspoon ground cumin, and 1/8 teaspoon cayenne. Remove husks and silk from 2 ears corn. Cut kernels off cobs (about 2 cups) and add to bowl. Rinse, stem, seed, and dice 1 red bell pepper (8 oz.). Add bell pepper, 1/2 cup diced red onion, and 1/4 cup chopped cilantro to bowl; stir into dressing. Peel, pit, and chop 3 firm-ripe avocados (1 1/2 lb. total). Add to bowl and gently mix, taking care not to smash the avocado too much.