In a small bowl, whisk together the coconut aminos, rice vinegar, tomato paste, honey, and arrowroot powder until smooth to create the sauce.
Heat the sesame oil in a large skillet or wok over medium-high heat until shimmering.
Season the diced chicken breast with sea salt and black pepper, then add it to the skillet and cook until golden brown and no longer pink.
Remove the chicken from the skillet and set aside on a plate.
Add the red bell pepper, green bell pepper, red onion, ginger, and garlic to the same skillet, sautéing for 3-4 minutes until the vegetables are tender-crisp.
Stir in the pineapple chunks and cook for 1 minute to allow them to warm through and slightly caramelize.
Return the cooked chicken to the skillet and pour the prepared sauce over the chicken and vegetable mixture.
Toss everything together for 1-2 minutes until the sauce thickens into a glossy glaze that coats every piece.
Serve the stir-fry immediately over the warm cooked brown rice.