In a medium bowl, combine egg yolk, 1 tablespoon of cornstarch and soy sauce. Whisk it together, add pork and marinate for a minimum of 30 minutes. There shouldn't be lots of sauce, but If you feel like a little more is needed, add ½ tablespoon of cornstarch and 1 tablespoon of soy sauce.
Heat the olive oil in a large skillet (preferably wok) over medium-high heat.
Remove pork from the marinade, dredge it in 3 tablespoons of corn starch and deep fry on both sides until golden brown. Transfer the meat onto a paper towel and discard the oil.
Heat a new portion of oil and deep fry the pork for another couple of minutes. It will make the meat crispy on the outside and juicy on the inside. Transfer the meat onto a paper towel.
Heat the olive oil in a large skillet over medium heat and cook ginger for 1-2 minutes.
Add bell pepper and stir-fry for 2 minutes.
Add pineapple and continue stir-frying for another 2 minutes.
Add white wine vinegar, sugar, tomato paste diluted in pineapple juice and salt to a taste.
One tablespoon of corn starch dilute in 2 tablespoons of cold water and add it into a skillet. Add pork, give everything a nice toss, cook for 30 more seconds and remove from the heat.
Serve with a steamed rice or with a side salad.