Cut the chicken breast into bite-sized pieces and pat dry with a paper towel.
In a small bowl, whisk together the coconut aminos, apple cider vinegar, and arrowroot starch until smooth.
Season the chicken pieces with sea salt and black pepper, then lightly dust with a tiny pinch of extra arrowroot if desired for extra crispiness.
Heat the avocado oil in a large skillet or wok over medium-high heat.
Add the chicken to the skillet in a single layer and sear for 3-4 minutes per side until golden brown and cooked through.
Remove the chicken from the pan and set aside.
In the same skillet, add the bell peppers, snap peas, minced garlic, and grated ginger, sautéing for 3 minutes until tender-crisp.
Add the pineapple chunks and the prepared sauce to the skillet, stirring constantly as the sauce thickens and bubbles.
Return the chicken to the pan and toss to coat everything in the glossy sauce.
Serve the stir-fry immediately over the warm cooked brown rice.