Sear the beef: Heat the olive oil in a large cast iron pan over medium-high heat. Sear the beef for a few minutes on each side until browned. Transfer to a slow cooker or crock pot.
Deglaze the pan: Add a bit of beef broth (or water) to the pan and scrape up the brown bits. Pour this into the slow cooker.
Add seasoning: Add paprika, chili powder, chipotle sauce, beef broth, vinegar, lime juice, onion, garlic, oregano, cumin, bay leaf, and salt and pepper to the slow cooker. Stir to combine.
Slow cook: Cook on high for 4 hours or on low for 6–8 hours until the beef is fork-tender and easily shreds.
Shred the beef: Once done cooking, use two forks to shred the beef directly in the slow cooker. Keep warm.
Make the guacamole: Mash the avocado with a fork until smooth. Stir in cilantro, garlic, and lime. Season with salt and pepper to taste. Refrigerate until serving.
Make the beans: Heat olive oil in a saucepan over medium heat. Sauté garlic and red onion until softened. Stir in cumin, then add black beans and 2 TBSP water per serving. Season with salt and pepper. Simmer for 15–20 minutes.
Warm the tortillas: Slightly warm tortilla shells on both sides in a skillet over medium heat.
Mix the margarita: Combine honey, water, orange juice, lime juice, and tequila (if using). Stir well. Serve over ice if desired.
Serve: Layer the tortillas with shredded beef and spoon sauce over top. Garnish with shredded cheese and jalapeño, if using. Serve with tortilla chips, guacamole, black beans, and margarita.