01 - Whisk together olive oil, lime juice, minced garlic, smoked paprika, cumin, chili powder, oregano, salt, and pepper in a large bowl. Add flank steak and coat thoroughly. Cover and refrigerate for at least 20 minutes, up to 2 hours for deeper flavor penetration.
02 - Heat grill or grill pan over high heat until properly preheated. Remove steak from marinade and allow excess to drip off.
03 - Place steak on hot grill and cook for 4–5 minutes per side for medium-rare doneness, adjusting time to achieve preferred internal temperature. Transfer to cutting board, tent loosely with foil, and rest for 5 minutes.
04 - While steak rests, heat 1 tbsp olive oil in large skillet over medium-high heat. Add sliced bell peppers and onion. Season with salt and pepper. Sauté until tender and slightly charred, approximately 6–8 minutes.
05 - Place tortillas on grill or in dry skillet over medium heat for 30 seconds per side until pliable and warmed through.
06 - Cut rested steak thinly across the grain to ensure tenderness.
07 - Arrange sliced steak and sautéed vegetables on large platter. Accompany with warmed tortillas, avocado slices, sour cream, salsa, cilantro, and lime wedges for guest assembly.