Pat the chicken breast dry with paper towels and toss with arrowroot powder, sea salt, and black pepper until evenly coated.
Heat the avocado oil in a large skillet or wok over medium-high heat until shimmering.
Add the chicken to the skillet in a single layer and cook for 5-6 minutes, turning occasionally, until golden brown and crispy.
Remove the chicken from the skillet and set aside on a plate.
In the same skillet, add the sliced red bell peppers and sauté for 3 minutes until tender-crisp.
In a small bowl, whisk together the coconut aminos, rice vinegar, minced ginger, and minced garlic.
Return the chicken to the pan along with the pineapple chunks and pour the sauce over the mixture.
Toss everything together for 1-2 minutes until the sauce thickens into a glossy glaze that coats the chicken.
Garnish with sesame seeds and serve immediately.