Preheat oven to 400°F (204°C) and line a baking sheet with parchment paper.
In a large bowl, toss the sliced bell peppers with the olive oil. Transfer to the perimeter of a baking sheet, and add the salmon fillets to the middle.
Sprinkle the salmon with salt and pepper, then top with the pineapple slices. Place the baking sheet in the oven for 30 minutes.
After 30 minutes, plate, and enjoy!