In a small mixing bowl, whisk together the coconut aminos, apple cider vinegar, tomato paste, honey, minced ginger, and minced garlic to create the sauce.
Cut the chicken breast into bite-sized cubes and season with sea salt and black pepper.
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, stirring occasionally, until golden brown and cooked through. Remove chicken from the pan and set aside.
In the same skillet, add the chopped bell pepper, red onion, and pineapple chunks. Sauté for 3-4 minutes until the vegetables are tender-crisp and the pineapple begins to caramelize.
Return the chicken to the skillet and pour the prepared sauce over the mixture. Toss well to coat and simmer for 2 minutes until the sauce thickens into a glossy glaze.
While the chicken finishes, steam the cauliflower rice in a separate pan or microwave until tender.
Serve the sweet and sour chicken over the cauliflower rice and garnish with sesame seeds and sliced green onions.