Heat a large skillet over medium-high heat and add the ground beef.
Cook the ground beef, breaking it apart with a spatula, until it begins to brown, about 5 minutes.
Add the diced onion and minced garlic to the skillet and cook for another 3-4 minutes until the onion is translucent and the beef is fully cooked.
Stir in the ground cumin, chili powder, smoked paprika, salt, and black pepper. Cook for 1 more minute to toast the spices.
Remove the beef mixture from the skillet and set aside.
Wipe the skillet clean and reduce the heat to medium.
Place one tortilla flat in the skillet and sprinkle 1/2 cup shredded cheddar cheese evenly over half of the tortilla.
Spread 1/4 of the ground beef mixture over the cheese, then sprinkle 1 tablespoon chopped cilantro on top.
Add another 1/2 cup shredded cheddar cheese over the beef mixture, then fold the tortilla over to cover the filling.
Cook for 3-4 minutes until the bottom is golden brown and the cheese begins to melt.
Carefully flip the quesadilla and cook for another 3-4 minutes until the other side is golden brown and the cheese is fully melted.
Remove the quesadilla from the skillet and let it rest for 1 minute before slicing into 4 wedges.
Repeat the process with the remaining tortillas and filling.
Serve warm.