Preheat your oven to 425°F (220°C).
Place the peeled, cubed potatoes in a pot and cover them with water. Add a generous pinch of salt to the water. Bring to a boil and simmer for about 8-10 minutes or until the potatoes are fork-tender but not mushy. Rinse the potatoes in cold water and drain well..
Place the potatoes in a large bowl. Toss the diced potatoes with olive oil, chili powder, cumin, smoked paprika, cayenne pepper, salt, and pepper until well coated.
Spread the seasoned parboiled potatoes in a single layer on a baking sheet lined with parchment paper. Roast in the preheated oven for 30-35 minutes or until the potatoes are golden brown and crispy, flipping them halfway through for even cooking.
While the potatoes are roasting, wash and shred the lettuce. Prepare any additional toppings.
Once the potatoes have been roasted, take a separate pan or directly on the stove, warm the tortillas according to the package instructions.
Spoon the spicy potatoes onto each tortilla. Add your favorite taco toppings, such as salsa, guacamole, shredded lettuce, diced tomatoes, and vegan cheese.