Preheat oven to 400 degrees F (200 degrees C). Line a baking sheet with a silicon mat or parchment paper.

Place flour, salt, sugar, and grated cheese in a mixing bowl. Stir together until well mixed. Add rosemary; drizzle with olive oil and add water. Mix with a fork until mixture comes together in a fairly sticky dough and pulls away from the sides of the bowl, 3 to 5 minutes.

Transfer dough onto floured surface and add flour as you knead the dough. Knead until it no longer sticks to work surface, 4 to 5 minutes. Divide dough in half.

Dust work surface with flour. Roll out dough to 1/8-inch thickness or less. Brush or mist surface of dough very lightly with water. Sprinkle with coarse sea salt. Prick the entire surface of dough with the tines of a fork to prevent crackers from puffing too much when baking.

Cut each rolled out half into about 30 pieces with a pizza wheel. You can cut them out in squares, rectangles, or triangles--your choice. Transfer onto prepared baking sheet with a bench scraper or your floured fingers (dough will be very sticky).

Bake in preheated oven until perfectly browned and crunchy, 10 to 15 minutes, depending on the thickness.