In a medium bowl, whisk together the olive oil, fresh lime juice, minced garlic, and chopped cilantro.
Add the paprika, turmeric, dried oregano, crushed black peppercorns, crushed white peppercorns, and kosher salt. Stir until the spices are evenly distributed.
Place the beef flank steak into a large, resealable plastic bag or a shallow glass dish.
Pour the marinade over the steak, ensuring the meat is completely coated. Seal the bag (pressing out excess air) or cover the dish tightly.
Refrigerate and let the steak marinate for at least 2 hours, or up to 24 hours for maximum flavor and tenderness.
Remove the steak from the marinade and cook as desired on a hot grill or cast-iron skillet, discarding the leftover marinade.