Combine olive oil, lime juice, minced garlic, chili powder, cumin, smoked paprika, salt, and pepper in a shallow dish. Add the steak and turn to coat completely. Let it marinate for at least 15 minutes, though 30 minutes gives even better flavor penetration.

While the steak marinates, whisk together the crema, lime juice, and salt until smooth and creamy. The mixture should be pourable but not too thin. Slice cabbage into thin ribbons, dice the red onion, and chop the cilantro.

Preheat your grill or grill pan to medium-high heat. Remove the steak from marinade and let excess drip off. Grill the steak for 3-4 minutes per side for medium-rare, or until you see beautiful char marks forming.

Transfer the cooked steak to a cutting board and let it rest for 5 minutes. Slice against the grain into thin strips, about 1/4-inch thick.

Quickly warm tortillas on the grill for 30 seconds per side, or wrap in damp paper towels and microwave for 30 seconds. Fill each tortilla with sliced steak, cabbage, red onion, avocado, and a drizzle of lime crema. Top with fresh cilantro and serve with lime wedges.