In a large bowl, combine fresh corn kernels, diced red onion, diced tomatoes, lime juice, chili powder, cumin, cilantro, salt, and pepper. Mix well and set aside to let the flavors meld.

Preheat a cast-iron skillet or grill over medium-high heat. Lightly oil the surface to prevent sticking.

Divide the ground beef into eight equal portions. Roll each portion into a ball to help maintain moisture.

Place each beef ball on the heated skillet and immediately press down with a spatula to form a thin patty. Season with salt and pepper. Cook for about 3-4 minutes until browned, then flip.

Once flipped, add a spoonful of the corn mixture directly on top of each patty. Let this cook for another 2-3 minutes, allowing the juices from the meat to flavor the corn.

While the burgers finish cooking, heat the corn tortillas in a separate pan or directly over the flame until warm and slightly charred.

Assemble each taco by placing a smashed burger onto a warm tortilla, adding sliced avocado, crumbled feta, and a dollop of mayonnaise and sour cream.

Top with additional corn mixture and any desired toppings such as jalapeños or hot sauce. Serve immediately.