Whisk garlic, vinegar, oil, ground chile, oregano, cumin and salt in a small bowl. Place steak in a shallow baking dish and pour marinade over it, turning to coat both sides. Cover and refrigerate for at least 1 hour, turning once, or overnight.

Preheat grill to high heat. Oil the grill rack (see Tip). Grill the steak until desired doneness, 5 to 6 minutes per side for medium. Transfer to a plate, cover with foil and let rest for 5 minutes. Slice the steak very thinly across the grain. Serve warm or chilled.

To oil a grill: Oil a folded paper towel, hold it with tongs and rub it over the rack. (Do not use cooking spray on a hot grill.) When grilling delicate foods like tofu and fish, it is helpful to spray the food with cooking spray.

Ingredient note: Ancho chile peppers, one of the most popular dried chiles used in Mexico, are dried poblano peppers. They have a mild, sweet, spicy flavor. Ground ancho chile pepper can be found in the specialty-spice section of large supermarkets, or substitute ground chili powder with a pinch of cayenne.

MAKE AHEAD TIP: Marinate steak in the refrigerator for up to 1 day and/or refrigerate cooked steak for up to 1 day. Slice just before serving.