01 - Heat a large skillet over medium heat. Add ground beef and cook, breaking apart with a spatula, until browned and mostly cooked through, approximately 5 minutes.
02 - Stir in diced onion and cook for 2-3 minutes until softened. Add minced garlic and cook for 30 seconds until fragrant.
03 - Mix in tomato paste, cumin, chili powder, smoked paprika, oregano, salt, and black pepper. Stir thoroughly to coat the meat and onion mixture evenly.
04 - Pour in water and reduce heat to low. Simmer for 5 minutes until the mixture thickens slightly. Remove from heat.
05 - Warm taco shells according to package instructions.
06 - Spoon beef mixture into each shell. Top with lettuce, tomatoes, cheese, and sour cream. Garnish with cilantro if desired. Serve immediately with lime wedges.