Add avocado oil to a skillet over medium-high heat. Once the oil is hot, add seasoned potatoes to skillet. Next, add bell pepper and onion on top of the potatoes. Let potatoes cook on the first side until they get crunchy, about 7 to 8 minutes. Flip the potatoes, bell peppers, and onions and continue to cook until the other side of potatoes gets crunchy, about another 10 minutes.