For the Chicken
Pat chicken dry with a paper towel. Trim away any excess fat. Cut into 1/2″ diced cubes.
In a medium sized bowl, whisk together the eggs.
Arrange an assembly line as follows: first a bowl with the chicken, second the bowl with the scrambled eggs, then third a bowl with the cornstarch.
Place the chicken into the egg mixture to fully coat the pieces. Then coat each piece of chicken in the cornstarch. Make sure all sides of the chicken have been coated and shake off any excess. Set the breaded chicken on a plate or a small baking sheet.
Preheat a large skillet over medium heat. Once the pan is hot, add in 2 Tablespoons of the canola oil.
Place the chicken pieces one by one into the hot skillet and allow the chicken to form a golden brown crust on the bottom before flipping it. Be sure to not crowd the pan – if the chicken pieces touch each other they will not get crispy. You will probably need to cook the chicken in multiple batches.
When chicken is crispy and reaches an internal temperature of 165F, remove and place the chicken on a plate or baking sheet lined with paper towels to absorb excess oil.
Repeat the last two steps to cook the remaining chicken. If needed, add the remaining oil to the pan.
Set aside (keeping warm).
For the Sautéed Vegetables and the Sweet & Sour Sauce
Add the onion and pepper to the pan. Cook until soft, about 5-7 minutes, stirring occasionally.
While the onions and peppers are cooking, make the sauce. In a small bowl combine the orange juice, soy sauce (or tamari), rice vinegar, tomato paste, brown sugar, ground ginger, garlic powder, and cornstarch. Whisk to combine very well.
When the onions and peppers are soft, add the pineapple and 1/2 cup of water. The water will help the vegetables to cook down more and provide some steam to your pan. Continue to cook until the vegetables are very tender and most of the water has evaporated.
Pour in the sweet & sour sauce and the cooked chicken. Stir to evenly coat chicken and vegetables in the sauce. Allow the sauce to come to a simmer and cook for about 3 minutes, or until the sauce has thickened.
Remove from the heat and serve over brown rice or enjoy on its own. Optional: Garnish with sliced green onions and toasted sesame seeds.