Heat 1/4 cup water in a large skillet over medium heat.
Add spinach, sprinkle with salt, and cover. Cook for approximately 5 minutes, stirring occasionally, until spinach is wilted.
Drain spinach in a colander, rinse with cold water, and squeeze out excess water. Set aside.
Rinse and dry the same skillet. Spray the skillet with cooking spray and heat over medium-high heat. Place 1 to 2 tortillas in the hot skillet, and evenly spread a thin layer of cheese over the surface.
Separate cooked spinach leaves and spread over the cheese.
When cheese is mostly melted, scoop up about a tablespoon of salsa, draining as much liquid off as possible and drop it onto the open tortilla. Optionally add chicken to half the tortilla also (ingredient not listed above).
Carefully fold the side of the tortilla that does not have salsa on it over the top, creating a half-circle shape. Cook about one minute longer before removing to a plate. Repeat with remaining tortillas.