1. In medium bowl, whisk together soy sauce, mustard, sugar and ginger; set aside.
2. In large, non-stick skillet, over high heat, toast sesame seeds until golden brown, about 4 minutes; remove from pan and set aside.
3. In same skillet, saute onion and garlic in oil until soft, about 5 minutes, if desired, discard garlic clove halves. Add chicken and soy
sauce mixture to skillet. Cover and simmer, turning chicken over once, until chicken is cooked through.
4. Meanwhile, prepare spinach and pepper saute. To serve, place chicken on platter, pour sauce and vegetables over chicken and sprinkle with sesame
seeds. Place sauteed mixture on platter. Garnish with scallion fan.