Process almonds in a food processor until ground.
Beat butter at medium speed with an electric mixer until fluffy; gradually add sugar, beating well. Add almonds and extracts; beat at low speed until blended.
Combine flour and salt; gradually add to butter mixture, beating at low speed just until blended after each addition.
Divide dough in half; wrap each portion in plastic wrap, and chill at least 1 hour. Roll level teaspoonfuls of dough into ropes; place ropes 1 inch apart on lightly greased baking sheets. Bring ends of each rope toward center to form crescents. (Keep remaining dough chilled and ready for shaping.)
Bake at 300° for 17 minutes; cool on baking sheets 2 minutes. Gently roll in powdered sugar, and cool completely on wire racks.