Combine masa, water, and salt. Mix by hand, kneading thoroughly to form soft dough - not stiff, but not sticky. If dough feels too dry, add more water (one tablespoon at a time). Cover and let stand 5 minutes. Divide dough evenly into 8 pieces, and roll each piece into a ball. Cover with plastic or a damp cloth to keep the moisture in.
Cut 2 pieces of plastic ziptop bag 1-inch larger than the tortilla press.
Set large griddle (one that stretches of 2 burners) or 2 skillets on stovetop. Set heat under one end of griddle (or one skillet) at medium, and set heat under other end (or other skillet) at medium-high.
Open tortilla press, and lay in one piece of plastic. Lay dough ball in center, and top with second piece of plastic. Close press. Press gently enough to mash dough into 1/8-inch thick disc that measures roughly 5 to 6 inches in diameter. Carefully peel off top piece of plastic.
Unmold uncooked tortilla: Flip tortilla onto right hand (if right-handed). Top of tortilla should line up with top of index finger. Lay tortilla on ungreased medium-hot griddle (or skillet) by letting bottom of tortilla touch griddle, then lowering your hand slightly and moving it away from you - the tortilla will stick to the hot surface so you can roll your hand out from under it as it rolls down flat.
After about 30 seconds, the edges of tortilla will dry slightly and tortilla will release from griddle - before this moment, tortilla will be stuck. With a spatula, flip onto hotter side of griddle (or hotter skillet). After about 30 seconds, tortilla should be browned underneath. Flip. Cook 30 seconds more - tortilla should puff in places (a gentle press with spatula or fingers encourages puffing). Transfer cooked tortilla to basket or plate lined with towel or a cloth napkin.
Press and cook remaining tortillas. Stack each cooked tortilla on top of previous one. Keep tortillas well wrapped in towel to keep warm.
Tortillas can be stored in a sealed plastic bag in the ‘fridge for up to a week, if you don’t eat ‘em all right away!