In a large non-stick skillet over medium heat, add the onion, ginger, and cook for 2 minutes, stirring constantly. (if you are not using a non-stick skillet, add 1 tablespoon vegetable oil).
After 2 minutes, add the pineapple, bell pepper, and cashew, continue cooking, stirring, for 4 minutes or until the vegetables are tender but still crunchy.
Add the rice, soy sauce, and sesame oil, cook, stirring, 4 minutes, and mix. Season to taste and sprinkle with the green onion and cilantro, if desired.