Combine 1 1/4 cups sugar, salt and flour. Arrange 1/2 of strawberries and rhubarb in pastry lined 9 inch pie pan. Sprinkle with 1/2 of sugar mixture. Repeat with remaining fruit and sugar mixture; dot with butter.
Adjust top crust and flute edges. Brush top of pie with cold water and sprinkle on 1 tablespoon sugar. Cut steam vents. Bake in hot oven (425 degrees) for 40-50 minutes or until rhubarb is tender and crust is browned.