Place turkey between two sheets of heavy-duty plastic wrap; flatten to 1/2-inch thickness, using a meat mallet or rolling pin. Coat a large nonstick skillet with cooking spray, and place over medium-high heat until hot. Add turkey, and cook 5 to 6 minutes on each side or until lightly browned. Add asparagus and next 4 ingredients. Bring to a boil; cover, reduce heat, and simmer 6 to 8 minutes or until turkey is done.
Combine water and cornstarch, stirring well. Add cornstarch mixture to turkey mixture in skillet; cook, stirring constantly, 1 minute or until sauce is thickened. Remove turkey and asparagus from skillet, and place on a serving platter. Spoon sauce over turkey and asparagus.