In a small bowl, stir together the cumin, kosher salt, garlic powder, and cracked black pepper. This spice blend forms the base of the marinade and helps bring out the deep, smoky flavors of the meat.

Coat the carne asada thoroughly with the spice mixture. Slice the meat into thin strips, then dice it into bite-sized pieces. This makes for easy taco assembly and better flavor distribution in every bite.

Transfer the seasoned meat to a large resealable plastic bag or bowl. Add the sliced serrano pepper, diced tomato, and onion. Pour in the beer and mix well to coat. Let the meat marinate for at least 15 minutes—or refrigerate it for up to 1 hour for deeper flavor.

Heat canola oil in a large skillet over medium-high heat. Once hot, add the entire marinated mixture. Stir occasionally and cook for about 20 minutes, until the liquid has fully evaporated and the meat is nicely browned.

Heat the tortillas on a skillet or comal until warm and pliable. You can also microwave them under a damp paper towel for 30 seconds.

Spoon the hot carne asada into each tortilla. Top with diced white onion and fresh chopped cilantro. Add a squeeze of lime, a dollop of salsa, or a few slices of avocado for an extra kick.