Preheat oven to 350 degrees F. Line 2 cookie sheets with parchment paper.
Knead flour into cookie dough until smooth. Roll out dough so that it is 1/4-inch thick. With a knife or a pizza cutter, cut out 2-1/2-inch squares. Transfer to cookie sheets and bake until lightly golden, 8 to 10 minutes. Let cool completely on a wire rack.
Soften unwrapped fruit chews in the microwave on High for three seconds. Use a rolling pin to flatten chews, then cut shapes using cookie cutters or a knife.
Spoon frosting into a small zip-top bag; press out excess air and seal the bag. Snip a small corner from the bag and pipe small dots of frosting on top of the cookies, attach the fruit-chew shapes with frosting, and top with sprinkles, nonpareils, and decorating sugars.