In a small bowl, whisk together the pineapple juice, coconut aminos, rice vinegar, and arrowroot powder to create the sauce base.
Cut the chicken breast into bite-sized cubes and season evenly 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 until golden brown and cooked through, then remove and set aside.
In the same skillet, add the bell peppers, red onion, and pineapple chunks, sautéing for 3-4 minutes until the vegetables are crisp-tender.
Stir in the minced garlic and grated fresh ginger, cooking for 1 minute until highly fragrant.
Return the chicken to the pan and pour the sauce over the mixture, stirring constantly until the sauce thickens into a glossy glaze.
Steam or sauté the cauliflower rice separately until tender.
Serve the sweet and sour chicken immediately over the bed of cauliflower rice.