Marinade: Make the marinade by mixing together the tamari and sugar. Pour over the pork chops, let sit for 20 minutes. Add the cornstarch slurry and oil, mix well and set aside.
Sauce: Make the sauce by mixing together white miso paste, water, mirin, sake, ginger juice, sesame oil and cornflour slurry. Set aside.
Stir Fry: Heat a large frying pan with oil over high heat. Pan fry pork chops until both sides turn brown; 3-5 minutes. Reduce the heat to medium and continue to cook until done; about 3-5 minutes more. Set aside.
Heat the same frying pan with oil over high heat. Stir fry the onion with salt until soft; 3-4 minutes.
Stir in the sauce and heat through; 2-3 minutes. Stir in the pork chops and mix well. Garnish with seaweed and sesame seeds before serving.
To make ginger juice, blend ginger in a food processor or finely dice. Place into a fine cloth and squeeze out the juice.
If your local supermarket doesn't stock tamari, miso paste, mirin, sake or nori, you can find them in Asian speciality shops.