1. Combine mirin and egg in a medium bowl, stirring with a whisk. Add chicken; toss to coat. Let stand 5 minutes; drain well.
2. Combine powdered peanut butter and next 3 ingredients (through sugar) in a bowl, stirring with a whisk. Add chicken; toss well to coat. Heat a large skillet over medium-high heat. Add oil to pan; swirl to coat. Add chicken; cook 3 minutes on each side or until done. Remove chicken from pan; keep warm.
3. Heat pan over high heat. Add onions and bell pepper; stir-fry 1 minute. Combine 5 tablespoons water and next 4 ingredients (through Worcestershire) in a bowl, stirring with a whisk. Add chicken and ketchup mixture to pan; cook 1 minute, tossing to coat.
4. Divide rice among 4 plates; top with chicken mixture. Sprinkle evenly with cilantro leaves and sesame seeds.
MyRecipes is working with Let's Move!, the Partnership for a Healthier America, and USDA's MyPlate to give anyone looking for healthier options access to a trove of recipes that will help them create healthy, tasty plates. For more information about creating a healthy plate, visit www.choosemyplate.gov.