Prepare the brown rice according to package instructions and set aside in a warm bowl.
In a small glass jar, whisk together the tamari, rice vinegar, grated ginger, and minced garlic to create the sesame-ginger glaze.
Season the chicken breast evenly on both sides with sea salt and black pepper.
Heat the toasted sesame oil in a medium skillet over medium-high heat until shimmering.
Place the chicken in the skillet and sear for 5-6 minutes per side, or until the internal temperature reaches 165°F.
Pour the prepared glaze into the skillet during the final 60 seconds of cooking, turning the chicken to ensure it is fully coated and the sauce has slightly thickened.
Remove the chicken from the heat and slice into thin strips or bite-sized cubes.
Assemble the bowl by layering the cooked brown rice at the bottom, then topping with the glazed chicken, sliced cucumber, shelled edamame, and avocado slices.
Garnish the bowl with sesame seeds and any remaining glaze from the pan before serving.