01 - Heat olive oil in a large skillet over medium heat. Add chopped onion and cook until softened, about 2 to 3 minutes.
02 - Add ground beef to the skillet, breaking it up with a spatula, and cook until browned and fully cooked through, approximately 6 to 8 minutes.
03 - Stir in chili powder, cumin, smoked paprika, garlic powder, onion powder, cayenne pepper (if using), sea salt, and black pepper. Cook for 1 to 2 minutes until spices become aromatic.
04 - Remove the skillet from heat and allow the seasoned beef mixture to cool slightly.
05 - Wash and dry the lettuce leaves thoroughly, then arrange them on a serving platter to form taco shells.
06 - Spoon the seasoned beef into each lettuce leaf evenly.
07 - Top tacos with diced cherry tomatoes, sliced avocado, chopped cilantro, and jalapeño if desired.
08 - Serve immediately with lime wedges on the side for squeezing.