Drizzle chicken with 1 tablespoons lemon juice and the sesame oil.
In a bowl, mix 1 cup broth, remaining lemon juice, soy sauce, and sugar together and set aside.
In a small dish, mix 1/4 cup chicken broth with cornstarch and set aside.
Heat the vegetable oil in a non-stick skillet over medium high heat and then stir fry the chicken for 2 minutes. Add in the carrots, peas, and bell pepper and cook another 2-3 minutes or until chicken is done.
Add the lemon broth mixture to the pan and bring to a boil. Stream in the cornstarch mixture while stirring. Add the lemon slices and cook until sauce has thickened. Remove from heat.
Serve over rice and garnish with green onions and sesame seeds. Drizzle with more soy sauce if desired.