Mix potatoes, and powdered sugar. Stir in coconut, vanilla, and salt; blend well. Press into one large or two small pans so that candy will be about 1/2 inch thick. Melt chocolate over hot water, pour chocolate on top of candy. Cool and cut into squares.
Make haystacks by forming white mixture into cones 1-inch high. Allow to stand uncovered for 20 minutes. Dip base of each cone in melted chocolate; place on waxed paper until chocolate hardens.
Yield: about 100 small haystacks