In a large bowl, slowly add warm water to masa harina (and ½ tsp salt, if desired), kneading until smooth (~2 minutes).
The masa should be moist but not sticky, like fresh playdough. Roll a ball and smush between forefingers and thumb. If the edges crack, add a bit of water to masa. If it sticks to your hand when smushed, add a bit more masa harina. Optional: Allow masa to rest (covered) for ~15 minutes to fully hydrate.
Preheat a comal or nonstick pan to medium-high. Roll the masa into ping-pong-sized balls (~40g each). Place a ball of masa at the center of a tortilla press, flattening it between two plastic liners.
Remove the uncooked tortilla from the liners and place onto the pan in a backhanded motion. Sear the first side for ~30 seconds or until the tortilla easily releases, then flip and sear the reverse side for ~30 seconds. Flip once more and cook for ~30 seconds or until the tortilla puffs.
Tuck into a tortilla warmer or kitchen towel to rest and become more pliable.
