Stir together Masa Harina, cheese, potato, baking powder and salt. Mix in the
water until dough is smooth and moist, but not sticky. Shape dough into 8 balls
about 2 to 2 1/2 inches in diameter. Between sheets of wax paper, roll the balls
into tortillas about 4 inches in diameter.
Heat 1 to 2 inches of vegetable oil in a small skillet until the oil ripples.
Dip a tortilla into the oil and fry until light brown and crisped, but still chewy.
Repeat with remaining tortillas, then drain them.
Put 2 tortillas on heatproof serving plates. Spoon equal portions of warm mild
red chile sauce and queso blanco or Monterey jack cheese over the tortillas. Bake
for 4 to 5 minutes at 400 degrees F, or until the cheese melts and becomes bubbly.
Top each serving with sliced scallions, shredded lettuce which has been tossed
with a splash of vegetable oil and vinegar, and sliced green olives, if desired.