01 - Heat vegetable oil in a large skillet over medium heat. Add finely chopped onion and sauté for 2-3 minutes until softened.
02 - Stir in minced garlic and cook for 30 seconds until fragrant.
03 - Add ground beef, breaking it up with a spatula. Cook for 5-6 minutes until fully browned and cooked through.
04 - Drain excess fat if necessary. Stir in chili powder, ground cumin, smoked paprika, dried oregano, salt, and black pepper until evenly combined.
05 - Pour in tomato sauce and water, mix well, and simmer for 4-5 minutes until slightly thickened. Remove from heat.
06 - Heat hard taco shells according to package instructions while beef simmers.
07 - Fill each shell with the seasoned beef, then layer with shredded lettuce, diced tomatoes, cheddar cheese, red onion, cilantro, sour cream, salsa, jalapeño slices (optional), and a squeeze of lime.
08 - Serve immediately to ensure shells remain crisp.