Step 1

Combine garlic, cilantro, orange juice, lager, lime juice, oil, salt, pepper, vinegar, cumin, and chile powder in a large baking dish or 1-gal. resealable plastic bag. Add steak and turn to coat in marinade. Cover (or seal) and chill, turning occasionally, at least 10 hours and up to 1 day.

Step 2

Prepare a grill for medium-high heat; oil grate. Grill onion halves, chiles, and tomatillos, turning often, until charred and tender, 10–15 minutes for onion and tomatillos, 8–12 minutes for chiles.

Step 3

Transfer vegetables to a blender and add garlic, lime juice, salt, pepper, garlic powder, cumin, 1 cup cilantro, and 3 Tbsp. oil. Carefully blend until salsa is mostly smooth (some texture is good but make sure there are no large chunks).

Step 4

Remove steak from marinade, letting excess drip back into dish (or bag); discard marinade. Grill steak, turning every minute or so, until charred and an instant-read thermometer inserted into thickest part registers 140° for medium, about 5 minutes. Transfer to a cutting board and let rest 10 minutes.

Step 5

Thinly slice steak against the grain, then cut into bite-size pieces. Transfer to a bowl and sprinkle with sea salt.

Step 6

Top tortillas with some steak, salsa, cilantro, and chopped onion. Serve with lime wedges for squeezing over and remaining salsa alongside.Do ahead: Salsa can be made 1 day ahead. Transfer to an airtight container; cover and chill. Loosen with a splash of water if needed before serving.