Add popcorn kernels to Kitchen Mill, and grind into flour. In large bowl, mix flour and water until consistency is uniform (about 10 minutes). The masa is ready when mixture doesn't stick to your hands. Make 20 golf-sized balls and set aside.
Cover top and inside bottom of tortilla press with piece of plastic. Place one masa ball in middle of press, and close press to form tortilla with diameter of 4½–5 inches. Pull back top of plastic from tortilla.
Place spoonful of sausage and slice of cheese on top of tortilla. Fold tortilla in half, and seal contents by pressing edges together with fingers.
Peel empanada away from plastic, and fry in oil at 450°F until empanada turns light brown.