In a saucepan, melt margarine over low heat. Add marshmallows and stir until completely melted. Cook over low heat 3 minutes longer, stirring constantly. Remove from heat. Add crispy rice cereal. Stir until well coated. Remove from pan and place on foil-lined cutting board. Press mixture into 15"x 10-1/2" pan coated with cooking spray. When slightly cooled, cut into heart shapes using a 3 1/2" heart-shaped cookie cutter. Write names on each heart with red decorating icing. Trim edges with red cinnamon candies, using prepared frosting to hold candies in place.