Preheat the oven to 400 F. Place the sweet potatoes on a sheet pan, and pierce the top of each with a paring knife. Bake for about 30 minutes, until tender when pierced with a paring knife. Take out and let cool on a rack. Can be done up to three days ahead of time, and refrigerated, tightly covered.
Make salsa: Combine the tomatoes, jalapeno, cilantro, the green parts of the scallions, and the salt. Stir and reserve.
Preheat the oven to 400 F, unless you are going to microwave the sweet potatoes. For the sweet potatoes, place the potatoes on an oven safe platter and slice the top open lengthwise and then across, making a cross, then peel back the skin.Scoop out about half of the flesh, place on the cutting board, and chop.Reserve. Place the sweet potatoes in the oven to heat for about 15 minutes. Alternatively,you can microwave the sweet potato skins until hot, about 2-3 minutes on high.
In a large skillet, heat the olive oil briefly over medium-high heat and add the white parts of the scallions. Stir for a few seconds, until they start to sizzle, then reduce the heat to medium low and add the garlic. Stir for a few seconds. Add the crumbles (or beans, if using) and chopped sweet potato flesh and stir until heated through, about 3 minutes. Sprinkle with chili powder,cumin and salt and stir to mix. Take off the heat.
Take the hot sweet potato skins out of the oven and fill with the sauteed mixture,then top with shredded cheese and salsa. Serve immediately.