In a large bowl, beat the peanut butter and butter until blended; gradually beat in confectioners' sugar and salt until smooth. Stir in crispy rice. Refrigerate until firm, 30 minutes. Roll into 1 inch balls and chill again.
Melt chocolate in the microwave. Dip balls into chocolate, allow excess to drip off. Place on a waxed paper-lined pan. Let stand until set.