In a skillet over medium heat, brown the ground beef with the onion, crumbling it as it cooks. Drain any excess fat.
Add the taco seasoning and salsa. Bring to a boil, then reduce and simmer for 10 minutes.
Sprinkle cheese on one half of a tortilla, then spread on some of the meat mixture. Fold the tortilla over and press to seal. Continue until all tortillas are filled.
--You can fry them on the stove top: Wipe out the skillet and return it to the stovetop over medium heat. Add a tablespoon of oil. Place the folded tortillas in the pan and fry for a couple of minutes on each side until browned and crispy.--You can bake them at 400°F for 10-12 minutes, flipping halfway.--You can air fry them at 400°F for 7-8 minutes, flipping halfway.