n a large skillet, cook the bacon over medium-high heat until crisp, about 5 minutes. Drain on paper towels and pour off all but 1/4 cup of grease from the pan.
To the fat in the pan, add the onions and cook, stirring, over medium-high heat until soft, about 3 minutes. Add the garlic, pepper, and salt and cook, stirring, for 30 seconds. Add the mustard and vinegar and cook, stirring to de-glaze the pan. Add the sugar and stir to dissolve. Add the cherries and cook, stirring, until slightly plumped and warmed through, about 1 minute. Remove from the heat and whisk in the oil. Return the bacon to the pan and adjust the seasoning, to taste.
In a large bowl, toss the spinach with the warm dressing. Divide the salad among 4 salad plates, arrange the orange segments around the edges, crumble the goat cheese over the top and serve.