Combine raisins, sugar, cornstarch and water in saucepan. Stir over medium heat until thickened. Set aside to cool. Meanwhile, cream butter and sugar. Sift together flour, soda and salt. Stir into creamed mixture. Add oats and 1 tablespoon water. Mix until crumbly. Firmly press half of mixture into greased 13×9-inch pan. Spread with raisin filling. Pat on remaining crumb mixture. Bake at 350°F for 40 minutes or until lightly browned. Cool.
For icing, mix sifted powdered sugar with cinnamon. Stir in milk until consistency for drizzling. Drizzle on bars.