01 - In a large skillet over medium heat, add ground beef and cook, breaking it apart with a spatula, until browned and mostly cooked through (about 5 minutes).
02 - Add diced onion and cook for another 2-3 minutes until softened. Stir in the 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 well to coat the meat and onion mixture.
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 a generous dollop of sour cream. Garnish with cilantro if desired. Serve with lime wedges.