Put 8 1/3 cups (2 L) of water to boil in a pot and pour in the finely chopped sauerkraut. Leave to boil until softened.
Braise the chopped leeks until softened, add the flour and once braised a bit, add the paprika too.
Pour the prepared roux over the sauerkraut, then add the rice and boil another 10-15 min.
It can be consumed both hot or cold.