In a large skillet over medium heat, cook the ground beef until browned, breaking it apart with a spoon, about 5-7 minutes.
Add the finely chopped onion and minced garlic to the skillet with the beef and cook until the onion is translucent, about 3 minutes.
Transfer the cooked beef mixture to the slow cooker.
Add the tomato sauce, kidney beans, chili powder, ground cumin, smoked paprika, salt, black pepper, cayenne pepper, and water to the slow cooker. Stir well to combine.
Cover and cook on low for 4 hours, stirring occasionally.
About 30 minutes before serving, add the hot dogs to the slow cooker, submerging them in the chili sauce. Cover and continue cooking on low.
When ready to serve, toast the hot dog buns if desired.
Place two hot dogs in each bun and spoon generous amounts of chili over the hot dogs.
Top each chili dog with shredded cheddar cheese, diced onions, and a drizzle of yellow mustard.
Serve immediately and enjoy!