In a small bowl, combine chicken, salt, pepper, soy sauce, vinegar and baking soda. Mix until well incorporated. Marinate for 30 minutes.
After 30 minutes, add the eggs into the marinated chicken and mix well.
Coat each chicken piece with cornstarch.
In a deep wok or pan over medium heat, deep fry chicken pieces for around 2-3 minutes or until cooked through and crispy.
Remove from the oil and drain in a plate lined with paper towels. Set aside.
In a wok or pan over medium heat, get 2 tablespoons of oil from the oil used for deep frying. Sauté ginger, garlic and onion. Cook until fragrant and translucent.
Add apple cider vinegar or white vinegar, pineapple juice and sugar. Let it simmer for a while before stirring.
Stir and toss in green, red and orange bell peppers and mix. Cook for around 2 minutes or until crisp-tender.
Add tomato ketchup and pineapple chunks/ tidbits and mix well. Cook for another 2 minutes.
Taste and season with more salt and pepper if desired.
When sauce thickens, add the fried chicken pieces and coat evenly.
Transfer to a serving plate/ pineapple boat (if using fresh pineapple).
Garnish with toasted sesame seeds and chopped spring onion.
Serve and enjoy!