In a small mixing bowl, whisk together the coconut aminos, rice vinegar, raw honey, and arrowroot powder until the starch is fully dissolved.
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 until shimmering.
Add the chicken to the pan and sear for 5-6 minutes, stirring occasionally, until golden brown and cooked through.
Add the chopped red bell pepper, sliced red onion, and pineapple chunks to the skillet, stir-frying for 3-4 minutes until the vegetables are tender-crisp.
Pour the prepared sauce over the chicken and vegetable mixture, tossing constantly for 1-2 minutes until the glaze thickens and coats everything beautifully.
Serve the hot stir-fry immediately over the warm cooked brown rice and garnish with sesame seeds.