Dice the chicken breast into one-inch cubes and season evenly with sea salt and black pepper.
In a small mixing bowl, whisk together the rice vinegar, coconut aminos, tomato paste, honey, grated fresh ginger, and minced garlic to create the sauce.
Heat the avocado oil in a large skillet or wok over medium-high heat until shimmering.
Add the chicken cubes to the skillet and sauté for 5-6 minutes until golden brown and cooked through, then remove the chicken 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 skillet and pour the prepared sauce over the mixture, stirring constantly for 2 minutes until the glaze is thick and glossy.
While the chicken finishes, steam the cauliflower rice in a separate pan with a splash of water until tender.
Divide the cauliflower rice into bowls and top with the sweet and sour chicken mixture, serving immediately.