Measure the cassava flour and salt into a food processor, blitz to combine. Add lard to the processor, blitz just a few times to break up the lard and distribute a little.
Add water to the food processor, blitz just long enough to combine.
With clean or gloved hands, pinch a little of the mixture together. It should hold well, without being sticky. If it doesn't hold together, add a small amount of water - just a few drops at a time - combine, and test again. If it's sticky, add a little more cassava flour, combine, and test again.
Dump mixture out onto a clean work surface, and gently knead to form a coherent ball of dough - without overworking it.
Divide mixture into 6 equal portions. Form each portion into a ball, flatten slightly into a disk shape.
Cut two pieces of parchment paper slightly bigger than the surfaces of your tortilla press.
Sandwich one disk of dough between the pieces of parchment paper, press in tortilla press. I like to turn it 90 degrees after the first press, and press a second time.Repeat with the other 5 dough pieces.
Heat a large nonstick pan over medium. Depending on the size, cook 1-3 of the tortillas for a couple minutes on each side, until dry, cooked through, and slightly browning on the high points.