Place lime juice, olive oil, garlic, salt and cayenne pepper in a small jar. Cover with lid and shake until ingredients are well mixed. In a salad bowl, combine beans, corn, avocado, bell pepper, Jalapeno pepper, tomatoes, green onions, and cilantro. Shake lime dressing, and pout it over the salad. Stir salad to coat vegetables and beans with dressing. Refrigerate for 1/2-1 hour prior to serving so that flavors can blend.