Preheat oven to 400.
Cut sweet potatoes in half lengthwise, set on a baking sheet, and bake cut side up for 30-40 minutes. Remove from oven and let cool. Once cool enough to handle, scoop out sweet potato flesh, leaving just the slightest bit in the skin. Discard the flesh.
Flip skins over so skin side is up. Brush with olive oil and sprinkle with sea salt, then bake for 10 minutes. Flip, brush insides with olive oil, and bake for 10 more minutes.
Remove skins and place a sprinkling of cheese in each, topping with bacon. Place back in the oven for 2-3 minutes, or until cheese is melted. Remove and top with green onions and greek yogurt (or sour cream, of course!)