In a bowl, combine the sugar and flour; stir in rhubarb and strawberries. Transfer to a greased 11 x 7 x 2 inch baking dish. Dot with butter.
For crust, combine the flour and salt; add oil and water. Stir with a fork until mixture forms a ball. Roll out between two pieces of waxed paper to an 11 x 7 inch rectangle.
Discard top sheet of waxed paper. Invert dough over filling and gently peel off waxed paper. Brush dough with milk; sprinkle with sugar. Bake at 425 for 40-50 minutes or until golden brown. Serve with ice cream if desired.