Chop the chicken breast into bite-sized cubes and season evenly with sea salt and black pepper.
In a small bowl, whisk together the coconut aminos, rice vinegar, tomato paste, honey, grated fresh ginger, and minced garlic to create the stir-fry sauce.
Heat the avocado oil in a large skillet or wok over medium-high heat until shimmering.
Add the chicken cubes to the skillet and sear until golden brown and cooked through, approximately 5 to 7 minutes.
Remove the cooked chicken from the skillet and set it aside on a plate.
In the same skillet, add the broccoli florets, sliced red bell pepper, and pineapple chunks, sautéing for 3 to 4 minutes until the vegetables are tender-crisp.
Return the chicken to the skillet and pour the prepared sauce over the mixture.
Toss all ingredients together for 1 to 2 minutes until the sauce thickens and coats everything in a glossy glaze.
Garnish the stir-fry with sesame seeds and serve immediately.