Cut the chicken breast into bite-sized cubes and season with sea salt and black pepper.
Place the chicken in a bowl with arrowroot powder and toss until each piece is evenly coated.
In a small jar, whisk together the rice vinegar, honey, tomato paste, and coconut aminos to create the sauce.
Heat avocado oil in a large skillet or wok over medium-high heat.
Add the chicken to the skillet, cooking for 5-6 minutes while turning occasionally until the exterior is crispy and golden.
Remove the chicken from the pan and set aside.
Add the sliced red bell peppers and pineapple chunks to the same skillet, sautéing for 3 minutes until the peppers are tender-crisp.
Return the chicken to the pan and pour the sauce over the mixture.
Toss everything together for 1-2 minutes until the sauce thickens and glazes the chicken and vegetables.
Garnish with sesame seeds before serving.