Slice the bottom off of the unshucked ears of corn and place them in the microwave, two at a time.
Cook on high for three minutes. Let the corn cool slightly and, using a potholder or dish towel, squeeze at the top. The husk and silk will slip off. Set aside and repeat with the other ears of corn.
When the corn is cool, cut the kernels off the cob, cutting close to the cob.
Combine the cider vinegar, olive oil, and salt and pepper in a medium-size bowl. Mix well. Add the onion and corn kernels and toss to combine.
Just before serving, add the basil and stir to combine. Serve immediately.
Leftovers keep well covered in the refrigerator for several days and are even better the next day.To cook the corn on the stove instead of the microwave, place the shucked corn into a large pot of boiling water over high heat. Cover the pot and turn the heat down to medium. Cook for 4-6 minutes. Drain.