Toss together apple, lemon juice, and 3 tablespoons sugar.
Cook apple mixture in a large nonstick skillet coated with vegetable cooking spray over medium-high heat, stirring often, 5 minutes or until tender and golden brown. Remove apple mixture from skillet, and set aside. Wipe skillet clean.
Beat cream cheese, condensed milk, and vanilla at medium speed with an electric mixer until smooth (2 minutes).
Place 1 tortilla in skillet coated with cooking spray over medium heat; spread with about 1/4 cup cream cheese mixture. Cook 1 minute or until filling bubbles. Spoon 1/4 cup apple mixture on half of filling; sprinkle with about 1 teaspoon pecans. Fold tortilla in half; cook 30 seconds to 1 minute on each side until browned. Repeat procedure with remaining tortillas, fillings, and pecans.
Combine remaining sugar and cinnamon; sprinkle over quesadillas. Cut each quesadilla into 3 wedges.