Combine popcorn and cranberries in a large mixing bowl and set aside. Combine the sugar, 3/4 c water, corn syrup, salt and vinegar in a small heavy saucepan. Over high heat bring mixture to a boil. Insert a candy thermometer and cook until mixture reaches 290 degrees, roughly about 14 minutes. Add the food coloring, stirring until desired color is reached. remove pan from heat. Pour hot syrup over the popcorn mixture, stir together with a wooden spoon until all kernels are well coated. Working quickly, use your hands to form small balls. Transfer those to wax or parchment paper, and let cool completely. Wrap in waxed paper or plastic wrap. Keep them in airtight container for up to 2 days.