Place the spinach in a bowl with sweet potatoes, cranberries, and pumpkin seeds. Heat a small skillet and cook off the bacon. When the bacon is crispy, add the onions. Cook until soft, then add the cranberries. Warm through then add the vinegar. Turn off the heat and add the dressing to the bowl. Toss the salad using tongs, season to taste, and divide between two plates. Garnish with goat cheese and serve.