In a medium bowl, combine the sliced chicken breast with cornstarch, 1 tablespoon of soy sauce, freshly ground black pepper, and sesame oil. Toss to coat and marinate for at least 15 minutes.

In a small bowl, whisk together 3 tablespoons of soy sauce, oyster sauce, rice vinegar, honey, grated ginger, minced garlic, and optional gochujang or sriracha until well blended.

Heat 1 tablespoon of olive oil in a large wok over medium-high heat. Stir-fry the sliced yellow onion for 2-3 minutes until transparent and aromatic.

Add the sliced red and green bell peppers and stir continuously for about 3-4 minutes.

Add the pineapple chunks and stir-fry for another 1-2 minutes, allowing them to soften.

Remove the vegetables and pineapple from the wok, then add another tablespoon of olive oil and spread the marinated chicken in a single layer. Cook for 3-5 minutes on each side until golden brown.

Return the sautéed vegetables and pineapple to the wok, pour the prepared sauce over the mixture and stir continuously for 1-2 minutes until the sauce thickens.

Garnish with chopped green onions and a sprinkle of fresh black pepper. Serve hot with steamed rice, quinoa, or cauliflower rice.