1. In a large pot, bring salted water to a boil. Add corn, and when water returns to a boil (about 3-4 minutes) remove cooked corn and set aside until cool enough to handle.
2. Using a sharp knife, carefully slice downward to remove the kernels from the cob.
3. In a large bowl, gently stir together corn, tomato halves, avocado pieces, and red onion.
4. Prepare dressing by combining whisking together all ingredients. Pour over salad and gently stir.