How to Make It
Preheat grill to medium-high (about 450°F). Place corn on oiled grates; grill corn, turning occasionally, until slightly charred, about 10 minutes. Transfer to a cutting board. When cool enough to handle, cut corn kernels off cobs, discard cobs, and place kernels in a medium bowl. Add mayonnaise, cilantro, lime juice, ancho chile powder, and 1/8 teaspoon salt; stir to combine. Set aside.
Sprinkle steak evenly with cumin and remaining 1/2 teaspoon salt. Increase grill temperature to high (450°F to 550°F). Place steak on oiled grill grates, and grill to desired degree of doneness, 1 minute and 30 seconds to 2 minutes per side for medium-rare. Transfer to a cutting board.
Grill tortillas until edges become charred, 30 seconds to 1 minute per side. Thinly slice steak across the grain, and divide among tortillas. Top with corn mixture and cheese; garnish with cilantro, and serve with lime wedges.