Preheat oven to 350 degrees. Cut chocolate into 1 inch pieces. Use metal blade in Cuisinart to process pecans with sugar until fine, about one minute. Add flour and salt and process until mixed, about one minute; scrape workbowl. Cut butter into one inch pieces; add to work bowl with vanilla and process until dough just comes together, about 20 seconds. Shape rounded teaspoons of dough into one inch balls. Place on a baking sheet and bake until set, about 20 minutes. Roll in confectioners' sugar while still warm; cool on wire rack. Makes about 60 cookies.