Place an 8- to 10-inch skillet over medium heat until hot. Lightly spray each side of the tortilla with oil.
Place the tortilla in the hot pan and cook 30 seconds to 1 minute or until lightly browned. Turn the tortilla over and repeat.
Remove from the pan and transfer to baking sheet.
In small bowl, combine the refried beans and a tbsp of water, and mix. Use a rubber or plastic spatula to spread the bean paste over the tortilla. Be careful to leave 1/4 to 1/2 inch of tortilla uncovered at the outer edge.
Gently spread the salsa evenly over the bean paste and sprinkle with the mozzarella cheese. Place in oven for 5 to 7 minutes or until the cheese is melted.