01 - Heat vegetable oil in a large skillet over medium heat. Add finely chopped onion and cook for 2 to 3 minutes until softened.
02 - Stir in minced garlic and cook for 30 seconds until fragrant.
03 - Add ground beef, breaking it apart with a spoon, and cook for 5 to 7 minutes until browned and fully cooked.
04 - Drain excess fat if necessary. Stir in chili powder, ground cumin, smoked paprika, dried oregano, cayenne pepper if used, salt, and black pepper. Cook for 1 minute to toast spices.
05 - Add tomato sauce and water. Stir to combine and simmer for 3 to 5 minutes until slightly thickened. Adjust seasoning to taste.
06 - Heat tortillas in a dry skillet or microwave until soft and pliable.
07 - Spoon beef mixture into each tortilla. Top with shredded lettuce, diced tomatoes, shredded cheese, sour cream, chopped cilantro, and jalapeños as desired.
08 - Serve tacos immediately with lime wedges on the side.