Preheat the oven to 400ºF. Puncture the sweet potatoes with a fork and place them in a baking dish. Bake until soft, and knife slides into the flesh easily, about 35 – 45 minutes depending on the size.
Meanwhile, prepare the quinoa mixture by heating the oil in a saute pan over medium heat. Add the rest of the ingredients (spinach to salt & pepper) and saute until warm. Keep warm until the sweet potatoes are cooked.
When the sweet potatoes are soft, remove them from the oven and let them cool for a few minutes. Once cooled, transfer them to a plate, split them open with a sharp knife and spoon the quinoa into the center.
Whisk together the tahini, lemon, salt, pepper, and water then pour on top of sweet potatoes. Garnish with fresh chives and red pepper flakes. Serve immediately and enjoy!