Drain and rinse the canned black beans thoroughly and transfer them to a large mixing bowl.
Add the fresh corn kernels to the bowl, either grilled or boiled, for sweetness and texture.
Halve the cherry tomatoes and add them to the mixture, bringing in bright color and juiciness.
Finely chop the red onion and stir it into the bowl for sharpness and crunch.
Chop the fresh cilantro and sprinkle it over the ingredients for a fresh, herbal flavor.
Pour lime juice and olive oil over the salad, then toss everything together gently to combine and coat evenly.
Season with salt and pepper to taste, adjusting flavors as needed for balance.
If desired, fold in diced avocado for creaminess and feta cheese for added richness.
Give the salad a final gentle toss to incorporate any optional ingredients and flavors.
Cover the bowl and refrigerate for at least 10 minutes to let the flavors meld and serve chilled.
Serve the black bean salad in bowls, garnished with extra cilantro or feta if desired, and enjoy its fresh, vibrant taste.