Make the dough: In a large bowl whisk the masa harina, the flour and the salt and start adding the water gradually. Knead until the dough comes together in a ball. It should be soft and smooth.
Preheat a heavy skillet or griddle over medium heat. It should be hot when you cook your gorditas,
Divide the dough into 8 equal balls. With the palms of your hands or using a tortilla press, press them down into 3.5" discs, to a thickness of 1cm (.19 inch).
Cook the gorditas on the hot griddle/skillet for about 5 minutes on each side, until fully cooked inside. You can fry them, once you cooked them on the griddle, in hot vegetable oil for 1 - 2 minutes for each side, although this step is optional. See notes to air-fry your gorditas to give them a "fried" feel.
Carefully open with a knife one side (go around the edge about 3/4 of the way; do not completely cut off the top) of your gorditas and fill them with 2 -3 tablespoons of warm refried beans. Garnish and enjoy warm with your favorite salsa.