1. To make the salsa, combine black beans, avocado, corn, tomatoes, red onion, jalapeño, cilantro, and lime juice in a medium bowl. Season with salt and pepper, to taste. Set aside.
2. Preheat grill to medium high heat. Slice prepared polenta into rounds and lightly brush both sides with olive oil. Place polenta rounds on the hot grill and cook for 2-3 minutes or until rounds have grill marks. Flip and cook for an additional 2-3 minutes. Remove grill.
3. Top polenta rounds with salsa and serve immediately.
Note-the polenta rounds are good served warm or at room temperature. You can pick them up and eat them with your hands, but it gets a little messy. We usually use a plate and fork!