Remove the steak from the refrigerator and let it sit at room temperature for about 10–15 minutes, then pat it dry thoroughly with paper towels to ensure a perfect sear.
Season the steak evenly on both sides with paprika, cumin, chili powder, salt, and black pepper, pressing the spices gently into the meat so they adhere well.
Heat a skillet over high heat and add olive oil, allowing it to become hot but not smoking before placing the steak into the pan.
Cook the steak for about 3–4 minutes on each side without moving it too much, allowing a golden crust to develop while locking in juices.
Remove the steak from the pan and let it rest on a cutting board for at least 5 minutes so the juices redistribute throughout the meat.
While the steak rests, mix Greek yogurt, lemon juice, and a pinch of salt in a bowl until smooth and creamy, adjusting seasoning to taste.
Slice the rested steak thinly against the grain using a sharp knife to ensure each piece is tender and easy to chew.
Warm the tortillas in a dry pan or microwave until soft and pliable, making them easier to fold and enhancing their flavor.
Assemble each taco by placing sliced steak onto the tortilla, followed by lettuce, tomatoes, onions, and a generous drizzle of the yogurt sauce.
Serve immediately while everything is warm, juicy, and full of flavor.