In a large bowl, add the sweet potatoes, drizzle with olive oil and sprinkle with salt, to taste. Toss to coat and arrange them on a baking sheet. Roast the sweet potatoes until they are soft but not mushy, about 10 to 15 minutes. Remove from the oven and reserve.
Coat a large saute pan with olive oil. Add the bacon and put the pan over medium heat. When the bacon has started to get crispy and brown, add the onions, season with salt and saute until the onions are very soft and aromatic. Add the apples and the scallion whites and saute for 3 to 4 minutes. Stir in the sweet potatoes, and saute until the sweet potatoes are cooked through and starting to become crispy, about 7 to 8 minutes.
Transfer to a serving platter and garnish with the scallion greens and pumpkin seeds.