Toss the onions in the salt, and set to the side to rest for at least 5 minutes, but preferably 20 minutes.
Shuck the corn, then grill or boil for 5 - 7 minutes. After the corn has cooled enough to handle, cut the kernels off the cub.
In a small bowl, mix together the mayonnaise, lime juice, garlic, smoked paprika, and cumin.
To a large bowl, add the corn, onion, cotija, and pickled jalapenos. Add the dressing and mix to evenly coat the salad.