Cut pork into 1"/2.5 cm cubes and place into a medium bowl with the marinade ingredients—Shaoxing rice wine, light soy sauce, sesame oil, and one teaspoon salt. Leave to marinate for 30 minutes.
Meanwhile, cut the bell peppers into 1"/2.5 cm squares and cut the spring onions into 1"/2.5 cm pieces. Peel and cut the carrots into 1"/2.5 cm pieces and cook in a small pan of boiling water for 4 minutes. Drain and set aside.
Whisk the egg and cornstarch in a large bowl until well combined into a light batter. Set it aside.
Pour the groundnut oil into a deep saucepan (or use your deep-fat fryer) and heat to 180°/350°F.
Lift the cubes of pork out of the marinade, leaving the marinade behind, and place them into the batter, coating each piece well. Working in batches, gently place into the hot oil and fry for 4-5 minutes until cooked and golden brown. Drain the fried pork pieces on a plate lined with a kitchen paper towel and keep warm. Continue frying until all the pork is cooked.
In a small bowl, stir two teaspoons of cornflour with one tablespoon of cold water and set aside.
In a bowl, combine the chicken stock, dark soy sauce, light soy sauce, sesame oil, rice wine vinegar, sugar, tomato puree (or ketchup), salt, and white pepper. Place into a hot work and bring to a boil.
Add the vegetables to the sauce, stir well, then stir in the slurry. Bring the sauce back to a boil, then lower the heat to a simmer. Add the lychees (oranges or pineapple) and the crispy pork. Mix well to combine all the ingredients, then transfer to a serving platter. Serve immediately with steamed rice or noodles.