Cut the chicken breast into bite-sized 1-inch cubes and season evenly with sea salt and black pepper.
In a small glass bowl, whisk together the coconut aminos, rice vinegar, tomato paste, honey, and toasted sesame oil until the sauce is smooth.
Heat the avocado oil in a large skillet or wok over medium-high heat until it begins to shimmer.
Add the chicken cubes to the skillet and cook for 5-6 minutes, stirring occasionally, until they are golden brown and cooked through.
Remove the chicken from the skillet and set aside on a plate.
In the same skillet, add the minced garlic and grated ginger, sautéing for 30 seconds until highly fragrant.
Add the sliced bell peppers, broccoli florets, and pineapple chunks to the pan, stir-frying for 3-4 minutes until the vegetables are tender-crisp.
Return the cooked chicken to the skillet and pour the prepared sweet and sour sauce over the top.
Toss everything together for 1-2 minutes until the sauce thickens slightly and coats the chicken and vegetables in a glossy glaze.