Pat the chicken breast dry and cut into bite-sized 1-inch cubes, then season evenly with sea salt and black pepper.
In a small bowl, whisk together the tomato paste, coconut aminos, apple cider vinegar, honey, and minced ginger to create the sauce.
Heat the avocado oil in a large skillet or wok over medium-high heat until shimmering.
Add the chicken to the skillet and sear for 4-5 minutes until golden brown and cooked through, then remove and set aside.
In the same skillet, add the sliced bell peppers, red onion, and minced garlic, sautéing for 3 minutes until the vegetables are crisp-tender.
Stir in the pineapple chunks and cook for another minute until warmed through and slightly caramelized.
Return the chicken to the pan and pour the prepared sauce over the mixture, tossing constantly for 1-2 minutes until the glaze thickens and coats everything beautifully.