1. Combine the first 8 ingredients in a large bowl. Stir in chicken. Cover and marinate 30 minutes.
2. Place rice in a medium saucepan; cover with water to 2 inches above rice. Stir rice; drain. Repeat procedure twice. Add 1 1/2 cups water to drained rice in pan. Bring to a boil over medium-high heat. Cover, reduce heat, and simmer for 20 minutes. Remove from heat; let stand 10 minutes.
3. While rice cooks, bring 1/3 cup water to a boil in a Dutch oven. Add chicken mixture; bring to a simmer. Cover, reduce heat, and simmer 20 minutes. Uncover and simmer 10 minutes or until mixture thickens, stirring occasionally. Remove from heat; stir in green onion tops and spinach. Sprinkle with sesame seeds. Serve with rice.