Place sweet potatoes on a large baking sheet and drizzle olive oil over them, then sprinkle with salt and pepper. Roast at 425 degrees for 25 minutes or until fork tender. Set aside to cool.

While potatoes are cooling, prepare the dressing in a small bowl. Set aside. Place cooled potatoes, pineapple, and chopped vegetables in a large bowl and pour dressing over and mix well. Allow to chill in the fridge for at least an hour and a half. Stir prior to serving and garnish with green onions.