Preheat oven to 425°F. Line and grease a baking sheet. Add corn; drizzle with olive oil and sprinkle with salt. Bake for 20 minutes. Let cool.
Meanwhile, combine dressing ingredients.
In a bowl, combine roasted corn, tomatoes, cucumber, red onion, and avocado. Toss with dressing. If making ahead, toss everything together and store in the fridge and simply add the avocado fresh.