Lightly spray a pan with cooking spray and heat over medium heat. Place a tortilla into the pan. Spread the salsa sauce over half of the tortilla and top with cheese.
Then top with the ham, green onion and with a layer of cheese.
Slip spatula under the unfilled side, fold the tortilla over the filled side. Press down gently.
Cook until the quesadilla is golden brown on both sides and the cheese is melted, about 2-4 minutes per side.
Remove the quesadilla to a cutting board, and let it sit for 2-3 minutes. Using a large knife, cut the quesadilla into wedges.
Repeat with remaining tortillas and fillings. Serve with sour cream and additional salsa, if desired.