Combine cheese, flour, cornstarch, and salt in a food processor.

Add butter and pulse until the mixture resembles wet sand.

Gradually add water and pulse until the dough forms a ball.

Divide dough into two discs, wrap in plastic wrap, and refrigerate for at least 30 minutes.

Roll out dough on a floured surface to ⅛-inch thickness.

Use a pizza cutter to cut into 1-inch squares.

Poke a hole in the center of each square with a skewer.

Preheat oven to 350°F and line a baking sheet with parchment paper.

Transfer crackers to the sheet, sprinkle with sea salt, and bake for 25 minutes, rotating halfway through.

Cool completely before serving.