Place chopped potatoes in a microwave safe bowl. Cover with plastic wrap. Microwave for about 4 minutes, stirring halfway throughout.
Heat 3 tablespoons of canola oil over medium heat in a large nonstick pan. When oil is heated through, add potatoes to the pan. Season with salt and pepper, then stir. Cover. Cook for 3 to 5 minutes or until potatoes begin to brown on one side.
Flip potatoes so the other side can be cooked. Cook for an additional 3 to 5 minutes.
Slide potatoes to one side of the pan. In the open space, place the remaining 1 tablespoon of canola oil in the pan. Add peppers, onions, garlic powder, smoked paprika and additional salt and pepper if desired. Stir everything together. Cook for an additional 12 to 15 minutes, or until desired doneness is reached, stirring every couple of minutes.
Garnish with green onion before serving if desired.
Avoid stirring too often as it'll make it harder for the potatoes to get brown and crispy.