Start by peeling the potatoes and dicing them into uniform 1/2-inch cubes. Rinse the diced potatoes under cold, running water to remove excess starch (this will help with crispiness). Make sure to pat them dry thoroughly using kitchen paper or a clean dish towel.
Place a heavy-bottomed skillet over medium-high heat. Add the canola oil or butter and let it heat up until it shimmers or the butter is melted.
Add the potato cubes to the hot skillet in a single layer. Do this in batches if your skillet is too small. Sprinkle with sea salt, black pepper, and the optional garlic powder and/or smoked paprika powder. Cook for about 10-15 minutes, until the potatoes are golden brown and crispy on the outside but tender on the inside. Stir occasionally.
Transfer the potatoes to a serving plate using a slotted spoon to drain any excess oil. Sprinkle with the chopped parsley and serve hot.