In a large saute pan, heat the oil over medium-high heat. When the pan is hot, add the corn and jalapeno. Stir to coat with oil, season with salt, then let it sit undisturbed for a few minutes. Stir again, then let sit for a couple more minutes. You aren't looking for your corn to get too brown, just brown in a few spots. Remove the pan from the heat and add in the mayo, green onions, and a big pinch of smoked paprika. Let cool to room temperature.
While your corn is cooling, dice your tomato. You really do want to remove all the seeds and 'guts' of the tomato. The salad just gets too watery if you leave them in. I cut my tomato in quarters then use my thumb to scrape out the seeds. It's super easy, I promise, and worth the extra step.
In a medium bowl combine the corn, tomatoes, lime juice, cilantro, and queso fresco. Season with salt and fresh black pepper to taste. The salad at this point can be kept in the fridge for several hours or even overnight. Just before serving lightly mix in the avocado and enjoy!