Combine beer, 1 Tbsp lime juice , salt & pepper in a resealable gallon bag.
Add steak and combine well. Chill for at least 3 hours.
Heat oil in a small skillet. Add onion and garlic and sauté for 4 minutes. Let cool.
Salsa
Heat up the grill and grill tomatoes until charred on all sides. Once cooled, remove seeds from tomatoes.
Place tomatoes, onion mixture, 3 Tbsp lime juice and chipotle chili in a food processor. Season with salt & pepper and pulse until smooth. Place in a small bowl.
Grilling
Remove beef from the marinade and pat dry. Season with salt and pepper and grill until medium rare - about 3 minutes a side.
Let sit on cutting board for 10-15 minutes then thinly slice against the grain.
Grill the tortillas about 30 seconds per side.
Assembly
Serve beef, salsa, cheese, avocado, lime wedges and tortillas on plates and bowls and let everyone make their own tacos.
Notes
We like to serve this with wedges of watermelon and of course, more beer!