Toss the chicken breast pieces with cornstarch and white pepper. In a separate bowl, whisk the egg white until frothy and add in the coated chicken. Toss to coat.
In a wok or large 12-inch chefs pan or skillet, add in 2 tablespoons of extra light olive oil or coconut oil and heat on medium-high to high heat. Once hot, work in batches cooking the chicken 4 to 6 minutes a side or until fully cooked. Add more oil as needed.
Once the chicken is fully cooked, reduce the heat to medium and add all of the chicken back into the pan, along with the minced garlic.
Cook for 1 to 2 minutes before adding in the vegetables and pineapple. Pour in the sweet and sour sauce and increase the heat back to high, and bring the sauce to a boil.
Once the sauce is boiling, pour in the cornstarch slurry and simmer until the sauce thickens. Taste and season the sauce with kosher salt, to your preference.
Serve the sweet and sour chicken over cooked rice and garnish with sliced green onions, cilantro and more sambal oelek or sriracha if desired.