In a glass or ceramic baking dish, whisk the EVOO, garlic and chili powder for a marinade. Brush some on the corn. Add the steak to the marinade in the baking dish; turn to coat. Let marinate 15 minutes, turning halfway through.
Heat a grill or grill pan over medium-high. Remove the steak from the marinade and season with salt and pepper. Grill the steak to desired doneness, about 4 minutes per side for medium-rare. Transfer to a cutting board, tent loosely with foil, and let rest 5 minutes.
Grill the ears of corn over medium-high, turning often, until charred in spots, about 12 minutes. Slice the kernels off the cobs into a large bowl and toss with the cabbage and pico de gallo; season.
Chop the steak into bite-size pieces; divide among the tortillas and top with the prepared corn salsa.