Combine all the ingredients except the cornstarch in a large measuring cup or bowl and whisk to combine. Combine the cornstarch and 1 tbsp of water in a small dish and set both aside.
For The Chicken
Heat at least 1 inch of canola oil in a heavy bottom pan or wok to 375 degrees F. (approximately medium-high heat)
Season the chicken with salt and then coat with 1/3 cup of cornstarch. Dip each chicken piece in egg, then coat in flour before carefully placing in the hot oil. Work in batches, so you don't lower the temperature of the oil. Lay chicken pieces on a wire cooking rack until complete.
Remove hot oil from wok and leave just 1 tbsp of oil remaining. Add in onion, bell peppers and pineapple and cook over high heat until lightly charred, about 3 minutes.
Whisk the sauce again and pour into wok with peppers. Stir the cornstarch slurry again and add to sauce. Bring mixture to a light boil and cook until thickened, about 3 more minutes.
Finally, add in the cooked chicken pieces and toss to coat. Serve immediately and enjoy!
Notes
You can leave out the pineapple if you're not a fan.