Preheat the oven to 250 degrees F (120 degrees C). Line a baking sheet with parchment paper. Combine flour and salt in a bowl. Add water a few tablespoons at a time, mixing well after each addition, until dough comes together.
Knead dough on a lightly floured surface until smooth, about 10 minutes. Wrap in plastic; rest for 20 minutes.
Transfer dough to a floured work surface; knead until soft and pliable.
Roll out dough to ⅛-inch thickness. Cut into desired shapes with festive cookie cutters.
Transfer ornaments to the prepared baking sheet. Make a small hole in each for hanging using a toothpick or skewer.
Bake in the preheated oven until dry and hard, about 2 hours. Cool completely before decorating.
