In large pan or wok, heat 2 tablespoons of oil on high. Cook onions and peppers in oil for about 3-5 minutes, or until onions are soft. Do not brown onions, turn the temperature down if needed to prevent browning.
Add 1/4 cup vegetable oil to the pan and heat on high. While oil is heating up, combine the marinated pork with the cornstarch. Add meat mixture to the oil and stir fry until brown and crispy. Add back the onion/pepper mixture and the orange sauce. Cook, stirring constantly, until bubbly.