Heat a large skillet over medium heat and cook the ground beef until browned, breaking it up with a wooden spoon.
Add the diced onion and garlic, cooking until softened.
Stir in the chili powder, cumin, paprika, and cayenne pepper, and cook for 1-2 minutes to toast the spices.
Add the tomato sauce and water, then reduce the heat to low. Simmer for 5-7 minutes, stirring occasionally.
Season with salt and pepper to taste. Serve immediately or use as a filling for tacos, burritos, or nachos.