Put hominy, masa de harina, and salt in the work bowl of a food processor. Add hot water and process until dough forms a soft but firm ball.
Remove dough and knead briefly, then cover with plastic wrap or a damp clean towel and allow dough to rest at least an hour at room temperature.
Divide dough into 20 equal portions and roll each portion into a ball. Press each ball of dough out into a thin disk using a tortilla press lined with plastic sheets made from food storage bags. Alternatively, shape by hand or with a rolling pin, but dough is quite sticky so a tortilla press will give the best results.
Heat a cast iron skillet or comal over medium-high heat. Make sure the pan is thoroughly hot for best results. Cook each tortilla for 30 seconds on the first side, a full minute on the second side, and an additional 30 seconds on the first side. If you find tortillas are sticking to the pan, brush a very tiny bit of oil on the surface of the pan before cooking.