Warm the Water - In the microwave-safe bowl, heat up the water until warm, about 45 to 60 seconds to reach 100 to 110ºF (38 to 43ºC).
Make the Masa Dough - In a medium bowl, whisk together masa harina and salt. Add the warm water to the mixture and stir with a spatula or large spoon to combine. Use your hands to knead the dough until the texture becomes very smooth. The texture should be pliable and moist but not sticky.Test the consistency by rolling a small dough ball and flattening it. If the edges crack and don't hold together, add more water, about 1 teaspoon at a time, kneading until the consistency is reached. Add more masa harina if the dough becomes too sticky.
Roll the Dough - Make 16 balls, 2 tablespoon-sized, about 1 ½-inches wide. Cover with a damp towel to prevent them from drying out.
Press the Tortillas - Working one tortilla at a time, use a tortilla press lined with two pieces of plastic wrap to flatten the rounds into 5-inch wide tortillas. Lightly spray the plastic wrap with cooking spray if needed to prevent sticking.Alternatively, use scissors to cut open the seams of a large resealable plastic bag, leaving the bottom intact. Spray the inside of the bag with cooking spray. Place the tortilla ball in the center of the bag, and use a flat-bottomed pan or pie dish to press and flatten. If needed, use a rolling pin to roll out into a 5-inch circle.
Cook the Tortillas - Heat a 12-inch cast iron skillet or nonstick pan over medium-high heat. Add ½ teaspoon oil and use a paper towel to spread a thin film. Skip oiling if using a nonstick pan.Add one to two tortillas, and cook until the edges begin to dry, 30 seconds. Flip and cook for 30 seconds. Flip one more time, and cook until the tortillas start to slightly puff up, 30 to 60 seconds.
Keep them Warm - Transfer the tortillas to a kitchen towel and wrap them to keep them warm and steam. This allows them to finish cooking and become more pliable. Continue the rolling and cooking process with the remaining dough.
Notes
Storing Uncooked Dough Balls: Place rolled dough balls in a resealable plastic bag and use them within 3 days.
Storing Cooked Tortillas: Transfer to a resealable plastic bag and refrigerate for up to 5 days.
Reheating: Heat tortillas in a large skillet over medium-high heat for 15 to 30 seconds on each side until warm. Alternatively, wrap 4 tortillas at a time in a damp paper towel, place them on a plate, and microwave on high power until warm, about 30 to 45 seconds.