Start by boiling corn kernels if using fresh. Drain and cool.
In a large bowl, combine the cooled corn with cherry tomatoes.
Add the diced avocado to the bowl.
Finely chop the red onion and add it to the mixture.
Chop fresh cilantro and stir it in.
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.
Toss everything gently but thoroughly to combine.
Serve immediately or chill in the refrigerator for 30 minutes before serving.