In a small bowl, whisk together the coconut aminos, rice vinegar, honey, tomato paste, arrowroot powder, minced ginger, and minced garlic to create the sauce.
Cut the chicken breast into bite-sized pieces and season evenly with sea salt and black pepper.
Heat the avocado oil in a large skillet or wok over medium-high heat until shimmering.
Add the chicken to the skillet and sauté for 5-6 minutes until golden brown and cooked through, then remove and set aside.
In the same skillet, add the sliced bell peppers, red onion, and pineapple chunks, sautéing for 3-4 minutes until the vegetables are tender-crisp.
Return the chicken to the pan and pour the prepared sauce over the mixture.
Stir constantly for 1-2 minutes until the sauce thickens and creates a glossy coating over the chicken and vegetables.
Steam the cauliflower rice in a separate pan or microwave until tender.
Serve the sweet and sour stir-fry immediately over the warm cauliflower rice.