Preheat the oven to 400 degrees F.
In a large bowl, add the yams, drizzle with olive oil, and sprinkle with salt. Toss to coat and arrange them on a baking sheet. Roast the yams until they are soft but not mushy, 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 yams and saute until they are cooked through and starting to become crispy, 7 to 8 minutes.
Transfer to a serving platter and garnish with the scallion greens and pumpkin seeds.