Microwave the white and red icings until liquid and pourable, about 30 seconds for the white icing and 15 seconds for the red. Use the white icing to pipe a line around the edge of each cookie. Fill in the centers, evenly distributing the icing with a toothpick.
Add dots of red icing in circles or lines on the wet white icing and drag a toothpick through the dots, creating heart chains. Let stand until set, about 1 hour.