In medium bowl, mix together Masarica and salt; pour water into masarica mixture. Using wet hands, knead mixture until it comes together to form a large ball of dough. Roll dough into 12 balls.
Using tortilla press lined with plastic wrap, press each ball into 4 ½” diameter circle. (Keep balls of dough and pressed tortillas moist by covering with damp towels.)
Heat lightly greased comal, griddle, or cast iron pan on stove over medium heat. To dough circle, add one cheese slice and jalapeño strip (if using). Fold circle in half (half-moon shape), pressing edges to seal. Place tortillas on hot cooking surface. Cook until golden brown and toasted in spots and cheese melts, flipping once, about 6 minutes.
Serve with guacamole and salsita, if desired.
To make perfect tortillas without a Mexican tortilla press, try this: On flat surface, place one ball of dough between two pieces of plastic wrap. Using the bottom of a skillet, evenly press down until dough forms 4½” round.