Add potatoes to a large pot and cover with 1-inch of water. Set over high heat and bring to a boil. Boil for 10 minutes, or until potatoes are fork-tender. Drain and transfer to a mixing bowl.
Sprinkle the hot potatoes with salt, cumin, black pepper, garlic powder, and onion powder. Using a potato masher, mash the potatoes leaving some chunkiness for texture, or to your desired consistency.
Stir in the cheddar cheese and scallions. Adjust seasoning to taste.
Arrange tortillas onto a flat work surface. Spoon 1/4 cup of potato mixture to cover one half of each tortilla. Fold over each tortilla to form a taco.
In a large skillet, heat 1 tablespoon of oil over medium-high heat. When the oil is hot, add 4-6 of the prepared tacos. Cook for 1 minute on each side, or until lightly golden brown. Work in 2-3 batches, depending on skillet size, adding the remaining 1 tablespoon of oil, as needed. Serve warm.