Prepare the quick pickled vegetables according to your recipe and set them aside; they can be made 3–4 days ahead.
Whisk the marinade in a bowl: combine coconut aminos, toasted sesame oil, rice vinegar, and minced garlic.
Cut the chicken thighs into bite-sized pieces and place them in a zip-top bag.
Pour the marinade into the bag with the chicken, seal, and massage to coat. Refrigerate at least 20 minutes or up to 24 hours.
Cook the brown rice according to package instructions while the chicken marinates.
Heat a large skillet over medium-high heat until hot. Add the marinated chicken and any remaining marinade to the skillet.
Sauté the chicken, stirring occasionally, until cooked through and golden and most of the marinade has reduced and thickened, about 5–8 minutes.
Assemble bowls with cooked brown rice, the sticky garlic-sesame chicken, pickled vegetables, and sliced avocado.
Sprinkle each bowl with sesame seeds before serving.
