Scrub the potatoes well. Place in a large pot and add water just to cover. Heat to a boil, and then reduce heat and simmer for 20-25 minutes or until the potatoes are tender when punctured with a fork.
Drain the water, and cube the potatoes into approximately equal size.
Meanwhile in a nonstick skillet, cook the bacon over medium heat, flipping occasionally, until crispy. Remove bacon onto a plate with a paper towels, pat dry and crumble the bacon. Leave bacon grease in the skillet.
Add the vinegar, dijon, salt and pepper to the bacon grease. Bring to a low boil for 1 minute, then add garlic, stirring. Remove from heat.
In a large bowl mix the cubed potatoes, crumbled cooked bacon, bacon dressing, rosemary, and green onions. Serve hot or cold.