In a small bowl, whisk together the coconut aminos, rice vinegar, honey, tomato paste, minced fresh ginger, and minced garlic to create the sauce.
Cut the chicken breast into bite-sized cubes and pat them dry with a paper towel.
Season the chicken with sea salt and black pepper, then toss in arrowroot starch until each piece is lightly and evenly coated.
Heat the avocado oil in a large non-stick skillet or wok over medium-high heat until shimmering.
Add the chicken to the pan in a single layer and cook for 5-6 minutes, turning occasionally, until the exterior is golden brown and crispy.
Add the sliced bell peppers, red onion, and pineapple chunks to the skillet with the chicken, sautéing for an additional 3 minutes until the vegetables are tender-crisp.
Pour the prepared sauce over the mixture and toss constantly for 1-2 minutes until the sauce thickens into a glossy glaze that coats the chicken and vegetables.
Remove from heat and serve the stir-fry immediately over a bed of warm cooked brown rice.