Preheat oven to 200°F.
Cut chicken into bite-size pieces, about 1/2-inch cubes.
Crack egg into a medium bowl. Beat until frothy.
Place cornstarch in another medium bowl.
Pour enough oil to deep fry into a large skillet or pot. Heat to about 350°F.
Dip pieces of chicken, a few at a time, into bowl with beaten egg.
Transfer to second bowl and roll in cornstarch until fully covered.
Place in hot oil. Cook until golden brown.
Remove from oil and drain on paper towel-covered plate. Repeat until all chicken is fried.
When done, place chicken pieces on an oven safe plate. Place in preheated oven to keep warm.
Add water to a medium pot.
Add prepared onion and bell pepper. Bring water to boil. Reduce heat, cover, cook until peppers and onion are crisp-tender.
Removed and drain. Place vegetables on an oven safe plate or bowl. Place in preheated oven to keep warm.
In a medium pan add 1 1/2 cups water.
Add dried red pepper, garlic and ginger. Place on stovetop and bring to boil. Boil for about 5 - 6 minutes, until fragrant.
Using a slotted spoon or spider strainer, remove red pepper, garlic and ginger from boiling water. Discard solids.
To water, add sugar, salt and vinegar. Continue to boil, stirring until sugar dissolves.
Stir in cornstarch, a little at a time, stopping when the sauce gets to the desired thickness.
Add in red food coloring, for color, if desired. Stir to mix. Remove sauce from heat.
Taste. Add more salt, to taste, if needed.
Remove plates of chicken and vegetables from oven.
Place chicken on a serving plate.
Scatter vegetables and pineapple chucks on top of chicken.
Pour as much sauce as desired over top. Store any excess sauce in a tightly sealed container, in the refrigerator, up to a week.
Serve hot.