Preheat the oven to 375°F.
Line a large baking sheet with parchment paper or a silicone baking mat.
Heat the oil in a large skillet over medium heat.
Add the ground beef and diced onion.
Cook for six to eight minutes, breaking the meat into small crumbles.
Drain excess grease if necessary.
Add the minced garlic and cook for approximately 30 seconds.
Add the chili powder, cumin, paprika, garlic powder, onion powder, oregano, salt, and black pepper.
Stir until the meat is evenly coated.
Add the water and tomato paste.
Reduce the heat to medium-low and simmer for three to five minutes, until the filling is moist but not watery.
Stir in the optional lime juice.
Taste and adjust the seasoning.
Divide the shredded cheese into eight approximately ¼-cup piles on the prepared baking sheet.
Spread each pile into a thin four- to five-inch circle.
Bake for six to nine minutes, until melted and golden around the edges.
Let the cheese circles cool for 30 to 60 seconds.
Carefully lift each circle and drape it over a wooden spoon handle, baking-dish edge, or taco holder.
Let the shells cool completely.
Divide the taco meat among the eight shells.
Add your preferred toppings.
Serve immediately.
