COOK spaghetti as directed on package.
MEANWHILE, heat dressing in large skillet on medium heat. Add onions and green peppers; cook and stir 5 min. Stir in ham, chipotle peppers and garlic; cook and stir 3 min. Add tomato sauce; mix well. Cook 5 min. or until heated through, stirring occasionally.
DRAIN spaghetti; place in large bowl. Add 3/4 of the sauce mixture and Singles; mix lightly until Singles are melted. Top with remaining sauce.