Whisk together the flours and salt in a large bowl. Pour in the water and olive oil and stir to combine to render a shaggy, wet dough.
Turn the very soft dough out onto a floured surface and knead for 2 minutes or until smooth. If the dough sticks during kneading, sprinkle the work surface with additional flour.
Form the dough into a log approximately 12 inches long. With a sharp knife or bench scraper, cut the log into 12 even pieces and roll each piece into a ball. Cover with a clean cloth and let rest for 30 minutes.
Flatten a ball with your hands. Place it on a floured work surface and dust it with more flour. With a rolling pin, roll it out into a circle 7 to 8 inches in diameter. Add small amounts of flour as needed to prevent the dough from sticking as you roll it out.
Heat a dry, well-seasoned cast-iron skillet over medium-high heat. When the pan is very hot, place a tortilla in it. After 30 to 60 seconds, when air bubbles have formed on the surface, flip the tortilla and cook it for another 30 seconds. Transfer to a towel-lined bowl or basket and fold the towel over the top to keep the tortilla warm and soft.
Continue to cook the tortillas, transferring them to the bowl or basket. When necessary, carefully wipe out excess flour from the pan to prevent it from smoking. Serve the softest tortillas, on the bottom of the pile, first.
Reheat and soften any leftover tortillas by warming them for 20 to 30 seconds each in a hot skillet. Or place them in a steamer basket over a pot of simmering water.
Notes
If you prefer, make these with all-purpose flour and no whole wheat.