Dice the chicken breast into bite-sized pieces and season with sea salt and black pepper.
In a small bowl, whisk together the coconut aminos, rice vinegar, tomato paste, honey, minced ginger, and minced garlic 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 cook until browned and cooked through, approximately 5 to 7 minutes.
Remove the chicken from the pan and set aside, then add the diced bell peppers and red onion to the same skillet.
Sauté the vegetables for 3 to 4 minutes until they are tender-crisp.
Stir in the pineapple chunks and the prepared sauce, then return the chicken to the skillet.
Toss all ingredients together for 2 minutes until the sauce thickens and evenly coats the chicken and vegetables.
Steam the cauliflower rice in a separate pan or microwave until tender.
Serve the sweet and sour chicken immediately over the warm cauliflower rice.