In a medium bowl, mix together the egg, 1 tablespoon sugar, salt and 1 tablespoon soy sauce.
Add the pork cubes and gently toss to coat. Set aside.
In another medium bowl, mix together the white wine vinegar, brown sugar, 2 tablespoons of soy sauce, cornstarch, pineapple juice, and chicken stock, to make the sauce. Set aside.
In a large skillet over medium high heat, heat the 4 tablespoons of olive oil. Add the pork mixture and cook, stirring frequently, until the pork has browned on all sides and is cooked through, about 7 minutes.
Transfer the pork cubes to a plate and set aside.
Add the garlic, ginger, red and green pepper and onion to the skillet and cook for about 3 minutes, until vegetables are tender but still a bit crisp.
Add the pineapple chunks and the sauce. Cook, stirring constantly, until the sauce is no longer cloudy and has thickened a little.
Return the pork to the skillet and cook for 2 minutes more.
Serve immediately over a bed of white long grain rice garnished with green onions and sesame seeds.