Add oil to a cast iron skillet and heat over medium-high heat. Add corn, use a large spoon or spatula to push it into a single layer. (Depending on your pan, you might have to cook the corn in batches.) Let corn cook for at least 3 minutes before stirring (too much stirring and your corn will not char correctly).Stir the corn and push it back into a single layer. Cook for 3 more minutes, then repeat. Continue until corn is sufficiently charred (about 10-12 minutes total).In a large bowl, combine corn and all other ingredients. Stir and serve with lime wedges and fresh cilantro.