Combine 1 ¼ cups finely ground whole wheat flour, 2 tablespoons sugar, ½ teaspoon cornstarch, ½ teaspoon kosher or sea salt and ¼ teaspoon paprika in a large mixing bowl.
Scatter 4 tablespoons unsalted butter, cold and in pieces, on top. Using a pastry blender or your fingertips, work the butter into the dry ingredients until it resembles coarse cornmeal.
Drizzle ¼ cup cold water, and stir with a wooden spoon or spatula until combined.
Transfer to the counter and knead a few times until it comes together. Don't overdo it. The dough should be stiff but smooth with no dry spots. If it's too dry, you can add a teaspoon of extra water at a time.
Preheat the oven to 400°F (200°C).
Lightly grease baking sheets or line them with parchment paper.
Roll the dough (half at a time for easier handling) into a thin rectangle on a well-floured counter. They really need to be rolled thin so they bake crisp. Check frequently to make sure the dough isn’t sticking. If it is, gently scrape a spatula underneath to lift it, then flour the counter again.
Using a pastry wheel or large kitchen knife, cut squares about 1 ½ inches in diameter. To resemble store-bought crackers, you can make indentations in the crackers with the end of a brochette stick or something similar. This is optional and will not alter the flavor, but it will make them flatter when they bake.
Transfer the crackers carefully to the baking sheets. They don’t spread much so no need to space them a lot. Sprinkle with additional salt.
Bake the crackers until crisp and bronzed, about 5 to 7 minutes, always keeping an eye on them as they are thin and can brown quickly.
Cool on wire racks.
Store in an airtight container for about a week or more. Or freeze them in an airtight container between sheets of waxed or freezer paper for a month.