Heat the oil in a large pan over medium high heat. Season the chicken with salt and pepper to taste and add to the pan.
Cook the chicken for 6-8 minutes, stirring occasionally, until chicken is cooked through.
Add the red bell pepper and pineapple to the pan and cook for 4-5 minutes or until tender. Add the ginger and garlic and cook for 30 seconds more.
In a small bowl, whisk together the pineapple juice, soy sauce, chicken broth, hoisin sauce and brown sugar.
Add the sauce mixture to the pan and bring to a simmer.
Mix the corn starch with 1 tablespoon of cold water; stir until smooth.
Add the cornstarch mixture to the pan and stir to combine. Bring to a boil and cook for 1 minute or until sauce has just thickened.
Sprinkle with sesame seeds and green onions, then serve.