In a large pot of boiling water, cook corn until warmed through, 3 to 5 minutes. Rinse with cold water until cool.
Meanwhile, combine tomatoes, onion, avocado, and basil in a large bowl. In a small bowl, combine remaining ingredients to make the vinaigrette, whisking until blended.
Cut corn kernels off cobs and add to salad, then pour in vinaigrette and toss gently to combine.
Note: Nutritional analysis is per serving.