01 - Heat vegetable oil in a large skillet over medium heat. Add chopped onion and cook for 2-3 minutes until softened.
02 - Add minced garlic and cook for 30 seconds until fragrant.
03 - Add ground beef to skillet, breaking it up with a spatula. Cook for 5-6 minutes until browned and fully cooked.
04 - Drain excess fat if necessary. Stir in chili powder, cumin, smoked paprika, oregano, salt, and black pepper until evenly combined.
05 - Add tomato sauce and water. Mix thoroughly and simmer for 4-5 minutes until slightly thickened. Remove from heat.
06 - While beef simmers, heat hard taco shells following package instructions.
07 - Fill each taco shell with seasoned beef. Top with shredded lettuce, diced tomatoes, cheddar cheese, red onion, cilantro, sour cream, salsa, jalapeño slices (if desired), and a squeeze of lime.
08 - Present tacos promptly to maintain shell crispness and enjoy while warm.