Preheat the oven to 350ºF. Line a cookie sheet with parchment paper. Cream together the butter and sugar until light and fluffy. Beat in the salt and vanilla. Then add the pecans and potato chips and mix well. With a wooden spoon, stir in the flour just until it disappears. Roll the batter into balls about the size of a large walnut and place on the parchment-lined cookie sheet, allowing plenty of room for spreading. Coat the bottom of a heavy glass with butter and then dip in sugar. Press and twist to flatten each ball into a 3-inch circle. Bake 8 to 10 minutes or until the edges turn lightly golden brown. Transfer to racks to cool. For an optional garnish, melt the chocolate in a bowl over a pot of simmering water. Let cool slightly. When cool enough to handle, dip your fingertips, or the tines of a fork, in the chocolate and drizzle over the cookies. Refrigerate to set. This recipe yields about 24 cookies.