Prepare: Preheat grill to medium-high heat (between 400°F-450°F). Brush shucked corn and lime halves with 1 tablespoon oil.
Grill the corn: Grill the ears of corn with the lid closed for 10-15 minutes, turning occasionally, until corn is caramelized and dark brown spots appear on the kernels.
Grill the lime: While the corn is cooking, grill the lime halves cut side down on the cooking grates and remove them after grill marks appear, about 2-4 minutes.
Cool: Transfer the grilled ears of corn and lime halves to a large plate and let cool for 5 minutes, or until cool enough to handle.
Combine: Cut the grilled corn off the cob and transfer to a large mixing bowl. Squeeze the juice out of the grilled lime halves and add in all of the remaining ingredients. Toss together to combine, cover and refrigerate for 1 hour.
My favorite way to cut corn off the cob - Flip a small bowl upside down and it into a larger bowl. Stand the ear of corn on the small bowl and slice down with a knife. The kernels will fall into the larger mixing bowl and you'll be able to get every last kernel. Also easy cleanup!
Let the corn salsa rest in the fridge for 1 hour before serving. This helps all the flavors meld together and takes away some of the bite from the chopped red onions.
Middle of winter and can't get any fresh corn? Drain and rinse about 2 1/2-3 cups canned corn and saute it in a skillet with a little olive oil, until it gets nice and charred.