In a mixing bowl, combine olive oil, chili powder, cumin, garlic powder, salt, and black pepper. Rub the mixture onto the flank steak and let it marinate for at least 15 minutes.

Preheat the grill to medium-high heat.

Grill the steak for about 5-7 minutes on each side or until it reaches your desired doneness.

Remove the steak from the grill and let it rest for 5 minutes before slicing.

While the steak is resting, grill the corn until charred, then remove the kernels from the cob.

In a bowl, mix the grilled corn kernels with mayonnaise, Cotija cheese, lime juice, and cilantro.

Slice the grilled steak against the grain into thin strips.

Place a few slices of steak on each warmed corn tortilla.

Top with the elote mixture and garnish with additional chili powder if desired.

Serve with sliced radishes and lime wedges on the side.