Preheat the oven to 375°F(190C°). Line baking sheet with parchment paper or silicone baking mat. Set aside.
Put the flour, salt, sugar and cinnamon in a medium bowl and mix well. Add the melted butter and water and mix well with a spatula.
The dough will be a little bit sticky but easy to roll it out. Lightly flour the worksurface. Divide the dough in half and make balls out of each. Leave them on the counter to rest.
Make the cinnamon sugar mixture: Put sugar and cinnamon in a small bowl and mix well.
Sprinkle ¼ of the cinnamon-sugar mixture on to the work surface and start to roll one of the doughs. Roll out 16*6 inch long (40*16cm), 1/12 inch (2mm) thick dough. Cut out the dough into approximately 1,25 to 1,5 inches squares (3-4cm squares). Take them on to the baking sheet and prick them with a fork to prevent puffing. Sprinkle ¼ cinnamon- sugar mixture on top and bake for 12 minutes or until the edges are getting darker. Turn off the oven and let them stay there for 5-6 minutes or until the top of the crackers turn golden brown. Remove the baking sheet from the oven and let them cool for 10-15 minutes or until crispy. Watch the crackers carefully as the color tells when to turn off the oven and take them out of the oven. Do the same steps for the other dough.