Place potatoes in a medium pot, add cold water to cover potatoes by about 2 inches. Bring to a boil, reduce heat to gently simmer until potatoes are tender (about 15-20 min.). Drain, cut potatoes in half (optional).
While potatoes are cooking, heat a large skillet over medium heat, add bacon and onions and cook until bacon is crispy. Using a slotted spoon remove bacon and onions to a paper towel lined plate (reserving a small amount of bacon drippings in skillet). Add cooked potatoes to skillet, add back in the bacon and onions and stir to combine.
In a small bowl, whisk together vinegar, honey, mustard, garlic and salt/pepper. Slowly whisk in olive oil until thoroughly combined.
Divide arugula between bowls/plates, top with warm potato/bacon/onion mixture. Salt and pepper to taste. Drizzle dressing over salad and serve while potatoes are still warm.