Season the beef: Pat the roast dry. In a small bowl, mix salt, pepper, chili powder, cumin, smoked paprika, and oregano.
Rub the spice blend all over the beef.
Sear for flavor: Heat oil in a large skillet over medium-high. Sear the roast on all sides until browned, about 3–4 minutes per side. This adds depth and locks in juices.
Build the braising base: In the same skillet, reduce heat to medium.
Add onion and cook 3–4 minutes until softened. Stir in garlic and tomato paste; cook 1 minute. Pour in beef broth to deglaze, scraping up browned bits.
Stir in crushed tomatoes, orange juice, and vinegar.
Cook your way: Slow cooker: Place beef in the slow cooker, pour sauce over, cover, and cook on Low 8–10 hours or High 4–5 hours.
Pressure cooker: Transfer beef and sauce to the pressure cooker. Cook on High pressure for 55–65 minutes, natural release 15 minutes.
Stovetop: Place beef and sauce in a heavy pot. Bring to a simmer, cover, and cook on low for 3–3.5 hours, turning once or twice, until fork-tender.
Shred and adjust: Move the beef to a board and shred with two forks.
Skim excess fat from the sauce. Return shredded beef to the pot with the sauce and simmer 5–10 minutes to soak up flavor. Taste and adjust with salt, lime juice, or a pinch of sugar if needed.
Warm tortillas: Heat tortillas in a dry skillet or over a low flame until soft and lightly charred.
Keep them wrapped in a towel to stay warm.
Assemble tacos: Spoon beef into tortillas and top with cilantro, onion, a squeeze of lime, and any extras you like.