In a mixing bowl, combine tahini, water, lime juice, sesame oil, garlic, honey, salt, and pepper. Mix well until smooth.
Place chicken pieces in a resealable bag or container, pour the marinade over, seal, and shake gently. Marinate in the refrigerator for at least 30 minutes.
Cook brown rice according to package instructions.
Preheat oven to 425°F (220°C). Chop vegetables, toss with olive oil, salt, and pepper. Roast for 20-25 minutes.
Preheat grill over medium-high heat. Thread marinated chicken onto skewers and grill for 4-5 minutes on each side until fully cooked.
Assemble bowls with cooked brown rice, roasted vegetables, sliced chicken, scallions, cilantro, and sesame seeds.