Shuck the corn if using fresh ears.
Boil the corn in salted water for 3-5 minutes if using fresh.
Drain the corn and let it cool.
In a large bowl, combine corn, bell peppers, red onion, and cucumber.
In a separate bowl, whisk lime juice and olive oil.
Pour the dressing over the salad ingredients.
Add salt and pepper to taste.
Gently toss the salad to combine.
Add the halved cherry tomatoes and diced avocado.
Serve chilled or at room temperature.