Preheat oven to 350 degrees. In a mixing bowl, stir together the flour and icing sugar. Cut butter into flour mixture using a pastry blender or two knives until the mixture resembles coarse crumbs, about the size of peas. Pat minute into a 9x13 pan. Bake for 10-12 minutes.
While the crust bakes, stir together eggs, sugar, flour and salt. Fold in chopped rhubarb. Pour rhubarb mixture over hot crust. Reduce oven temperature to 325 degrees F and bake 30-35 minutes more.
Cool for 30 minutes and refrigerate squares to chill completely before cutting.