Start by heating a large pot on medium-high heat. Add the oil, and a few of the popcorn seeds.
Cover, and shake a few times. Once the kernels pop, add the remaining popcorn kernels, cover, and continue to shake the covered pot until all of the kernels have popped.
Add the lime zest to a large bowl. Uncover, and pour the popcorn into a large bowl.
Pour in the melted butter, salt, and give it a good toss. Toss a few more times until all of the popcorn is nicely coated with butter and salt.
Next add in the cotija cheese and chopped cilantro. Toss a couple of more times, then taste and season accordingly.