Add the water and olive oil to the starter discard and mix. Add the salt, flour and also the spices if you're using any. Mix.
Knead just enough to get a homogeneous dough.
Wrap the dough and let it rest for 30 minutes at room temperature.
Roll out the dough really thinly with a rolling pin on a floured surface. Make it 1mm thin. You can then cut it in strips or squares. Place them on a baking tray with baking paper or silpat.
Paint the crackers with a thin layer of olive oil and sprinkle them with salt flakes.
Bake the crackers in a preheated oven at 180°C/350°F for 8-10 minutos.