In a medium bowl, combine margarine, sugar, salt, vanilla and water, and mix well with hand mixer.

Combine flour and cornstarch and blend into margarine and sugar mixture. Chill dough overnight.

Roll out dough into a rectangle between sheets of plastic wrap. Mix brown sugar and cinnamon and sprinkle over dough.

Roll up from wide end of rectangle and cut into 1/2 inch slices.

Place on oiled baking sheet and bake at 350 degrees for about 18 minutes.