Gather all the ingredients.
If using fresh corn, boil it for 5 minutes and cool.
In a large bowl, combine the corn, cherry tomatoes, and bell pepper.
Add the finely chopped red onion and fresh cilantro.
In a small bowl, whisk together lime juice and olive oil.
Pour the dressing over the salad mixture.
Season with salt and pepper to taste.
Gently toss all ingredients to combine.
If desired, fold in diced avocado and black beans.
Let the salad chill in the refrigerator for at least 10 minutes before serving.