Begin by peeling and dicing the russet potatoes into small cubes. Place them in a large pot of salted water and bring to a boil. Cook the potatoes until they are fork-tender, which should take about 15-20 minutes. Drain and let them cool slightly.
Once the potatoes are cool enough to handle, transfer them to a mixing bowl. Use a fork or potato masher to mash the potatoes until smooth. Stir in the shredded queso fresco, and season with salt and pepper to taste.
In a frying pan, heat about ½ cup of vegetable oil over medium heat. While the oil heats, warm the corn tortillas in a separate pan or microwave for a few seconds to make them pliable.
Once the oil is hot, take a tortilla and spoon a generous amount of the potato filling onto one half. Fold the tortilla over to create a half-moon shape. Carefully place the filled taco into the hot oil, frying for about 2-3 minutes on each side or until golden brown and crispy.
Remove the tacos from the oil with a slotted spoon and place them on a paper towel-lined plate to drain excess oil. Repeat the process with the remaining tortillas and filling. Serve immediately with your favorite toppings.
