01 - Combine sliced beef, olive oil, garlic, chili powder, cumin, smoked paprika, oregano, salt, and black pepper in a large bowl. Toss to coat evenly and let marinate for 10 minutes or up to 1 hour for enhanced flavor.
02 - Heat a large skillet over medium-high heat. Place marinated beef in a single layer and sear for 2 to 3 minutes per side until browned and just cooked through. Remove from skillet and set aside.
03 - Add a drizzle of olive oil to the same skillet if necessary. Add sliced bell peppers and onion. Sauté for 5 to 7 minutes, stirring occasionally, until vegetables are tender and slightly charred.
04 - Return the seared beef to the skillet with the vegetables. Pour in lime juice and toss everything together. Cook for an additional 1 to 2 minutes to heat through.
05 - Transfer to serving dishes and accompany with warm tortillas and desired toppings such as sour cream, cilantro, lime wedges, and avocado slices.