Cut the chicken breast into bite-sized cubes and place them in a bowl.
Toss the chicken with arrowroot starch, sea salt, and black pepper until evenly coated.
In a small jar or bowl, whisk together the coconut aminos, rice vinegar, tomato paste, and honey to create the sauce.
Heat the avocado oil in a large skillet or wok over medium-high heat.
Add the chicken to the skillet and sear for 5-6 minutes, turning occasionally, until golden brown and cooked through.
Remove the chicken from the pan and set aside.
In the same skillet, add the sliced bell peppers, red onion, and pineapple chunks.
Sauté the vegetables for 3-4 minutes until they are tender-crisp and the pineapple begins to caramelize.
Return the chicken to the skillet and pour the prepared sauce over the mixture.
Stir constantly for 1-2 minutes until the sauce thickens and coats all ingredients in a glossy glaze.
Serve the stir-fry immediately over the warm cooked white rice.