Place potatoes and water in microwave safe dish. Cover and microwave for 4 min or until tender; drain.
In a large skillet, brown bacon until crisp. Save drippings in pan. Crumble bacon and set aside. Add kielbasa and onion to skillet. Cook until onion is tender. Add potatoes; saute 3-5 min longer or until kielbasa and potatoes are lightly browned.
Combine brown sugar, vinegar, mustard, thyme, and pepper; stir into skillet. Bring to a boil. Reduce heat; simmer uncovered for 2-3 min or until heated through. Add spinach and bacon; cook until spinach is wilted.