Cut the chicken breast into bite-sized pieces and toss in a bowl with the sea salt, black pepper, and arrowroot powder until evenly coated.
In a small jar or bowl, whisk together the pineapple juice, rice vinegar, coconut aminos, tomato paste, and honey until smooth.
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 sear for 3-4 minutes per side until crispy and cooked through, then transfer to a plate.
Add the broccoli, bell pepper, and snap peas to the same skillet and sauté for 5 minutes until tender-crisp and bright.
Return the chicken to the pan and pour the sauce over the mixture, tossing constantly for 1-2 minutes until the sauce thickens into a glossy glaze.
Garnish with sesame seeds and serve immediately while hot.