Place the chiles in a bowl and cover with hot water. Soak about 10 minutes, or until softened. Drain and discard the soaking liquid.
Place softened chiles in a blender along with salt and 1 cup (237 ml) warm water.
Strain through a medium-mesh strainer into a large bowl.
Add the dried masa and knead until the chile purée is evenly distributed through the dough. While kneading, add water as needed (approximately 1/4 cup, 59 ml) to form a soft, workable dough.
Let the dough rest a few minutes before dividing into balls and pressing.
Cut rounds from plastic to fit the tortilla press (This is a great way to reuse a plastic grocery bag).
Heat a well-seasoned comal or iron griddle over medium-high heat. If possible, set the comal at two temperatures: 325˚F (163˚C) and 375˚F (191˚C). The cooler side is for the first two turns of the tortilla. For the last turn of the tortilla, move it to the 375˚F (191˚C) side. This helps encourage puffing. Some chefs lay a tortilla directly on a burner flame for the last turn.
Divide dough into 12-15 balls and cover with plastic wrap or a damp towel to prevent the dough from drying out (this is very important).
Place a round of plastic on the tortilla press, and place a ball of masa on top of the plastic just slightly off center toward the hinge (this helps maintain an even thickness). Place a second piece of plastic over the ball of masa, flatten it slightly by hand, then close the lid and press. Some chefs like to turn the package 180 degrees and gently press again.
With the tortilla still pressed between the plastic sheets, place in one hand and use other to peel off the top sheet of plastic. (Plastic sheets may be reused to make remaining tortillas.)
Transfer the exposed side of the tortilla to the opposite hand. Fingers should be close together and the tortilla should be placed on the fingertips, not the palm. Peel off the remaining sheet of plastic.
Keeping palm up and nearly flat, gently lay the tortilla on the cooler side of the comal or iron griddle. Try to prevent the tortilla from folding over on itself when placing it on the comal. Cook for about 30 seconds, or until edges begin to firm.
Using a thin spatula, turn tortilla. Cook for about 1 minute more; the underside should begin to develop little blisters and slight freckles of brown.
Turn the tortilla over onto the hotter side of the comal, and after a few seconds, if the dough was the right consistency and the comal set to the right heat, the tortilla should puff up (if it doesn't, it is still perfectly usable). Coninue cooking until the underside has some brown spots and the tortilla is cooked through.
Place in a cloth-lined basket and keep covered while pressing and cooking the remaining tortillas.