Heat vegetable oil in a large pan or wok over medium-high heat.
Add diced onion, chopped Thai chili peppers, and minced garlic, and saute until fragrant, about 2 minutes.
Add shrimp to the pan and cook until pink and opaque, about 3-4 minutes. Remove shrimp from the pan and set aside.
In the same pan, add diced bell pepper and cook until slightly softened, about 2-3 minutes.
Add a bit more oil if needed, then add beaten eggs and scramble until cooked through.
Add cooked rice to the pan, breaking up any clumps, and stir-fry for about 2 minutes.
Stir in soy sauce, fish sauce, and lime juice, mixing well with the rice.
Add pineapple chunks and cooked shrimp back into the pan, stirring to combine everything evenly.
Season with salt and pepper to taste.
Garnish with chopped scallions and cilantro, if desired.