Preheat the grill to high and make sure it is hot.
Once the grill is hot, add the ears of corn directly to the grates. Cook for 3 to 4 minutes before rotating. Repeat this until the corn reaches the desired char. I usually grill it for about 8 to 12 minutes total, depending on the size. Once the corn has cooled enough, slice it off the cob.
In a large bowl, combine the corn with the onions, mayo, cilantro, cheese and lime juice. Add a pinch of salt and pepper. Add the tajin. Taste and season with more salt and pepper if needed. Or more tajin!
Heat a skillet over medium heat. With ground beef, I rarely add any oil to the skillet because it tends to be fattier. If needed, you can add 1 teaspoon of olive oil (of your oil of preference).
Once the skillet is hot, add the ground beef and break it apart with a wooden spoon.
Cook, stirring and breaking apart the beef often, until it begins to brown. Add in the cumin, paprika, garlic powder, chili powder, and a big pinch of salt and pepper. Stir well to disperse all the seasonings. Cook until the beef is just browned, breaking it into tiny crumbles as you go.
I like to add a bit of stock or water to the pan to keep the beef moist.
To assemble the tacos, add the ground beef to the tortillas and top immediately with the corn salad. Serve and enjoy!