In a small bowl, whisk together the vinaigrette ingredients.
Soak the corn in a large bowl of water for 30 minutes. Preheat the grill to medium. Drain the corn and place on the hot grill grates, grilling for 3 to 4 minutes on each side, or just until char marks begin to appear. Remove the ears of corn from the grill and let them cool. Cut the corn kernels off the cobs. (See my tip at the end).
In a large bowl, mix the corn kernels, tomatoes, basil and red onion.
Add the vinaigrette to the salad and toss. Season the salad with salt and pepper to taste. Cover and refrigerate until ready to serve.
This salad may be prepared up to 4 hours before serving.
Tip : Boil water in a large saucepan. When boiling, add the corn and when it return to a boil, boil them 2 minutes. Then remove from the water. And it's ready to grill on the bbq until you have the char marks. I tried it many times and it's perfect. It's what Ricardo suggest.