Combine olive oil, lime juice, garlic, cumin, salt, and pepper in a bowl to create the marinade.

Place the steak in a zip-lock bag, pour in the marinade, seal tightly, and refrigerate for at least 1 hour or overnight.

Preheat your grill to medium-high heat or use a hot cast-iron skillet.

Remove steak from marinade (discard excess) and grill for 3-5 minutes per side until medium-rare.

Transfer cooked steak to a cutting board and let it rest for 5 minutes.

Cut the steak against the grain into thin strips.

Warm corn tortillas on the grill or stovetop. Fill each tortilla with carne asada slices and top with cilantro, diced onions if desired, lime wedges, and salsa.