Step 1

Whisk vinegar, chili powder, oil, 2 teaspoons salt and garlic powder in a 9-by-13-inch baking dish. Add steak and turn to coat. Cover and marinate in the refrigerator for at least 1 hour and up to 24 hours.

Step 2

Make salsa about 20 minutes (and up to 2 hours) before cooking the meat: Gently combine tomatoes, jalapenos (or chiles) to taste, onion, cilantro, avocado, lime juice and the remaining 3/4 teaspoon salt in a medium bowl.

Step 3

Position rack in upper third of oven; preheat broiler.

Step 4

Place the steak on a rimmed baking sheet (discard the marinade). Broil 3 to 4 minutes per side for medium. Transfer to a clean cutting board and let rest for 5 minutes. Thinly slice against the grain. Serve the steak wrapped in warm tortillas and topped with the salsa and cheese.