In a large bowl cream together butter, sugar, salt and orange zest. Sift in flour and mix until just combined.
Roll one inch balls of dough and place on a ungreesed cookie sheet. Make a small hole in the center of each ball using your thumb or finger. Fill with jam and bake for 10 to 12 minutes or until golden brown around the edges.
In a small bowl mix together orange juice and powdered sugar. Drizzle onto the cooled cookies and let dry.