Whisk masa and salt in a medium bowl. Stir in 1 1/2 cups water; knead in bowl until dough forms. The dough should feel firm and springy and look slightly dry (think Play-Doh). Add more water by tablespoonfuls if too crumbly; add a little more masa if too wet.
Measure 1 heaping tablespoon dough and roll into a ball. Flatten on a tortilla press lined with a plastic bag. If tortilla crumbles, dough is too dry (add more water); if it sticks to the plastic, dough is too wet (add more masa). Repeat, pressing out 2 more tortillas.
Heat a large cast-iron skillet over medium-high heat; lightly brush with oil. Cook 2-3 tortillas until charred in spots and edges start to curl, 1-2 minutes. Turn; cook through, about 15 seconds. Transfer to a kitchen towel; fold over to keep warm. Repeat, in batches, with remaining dough.
