Preheat the grill to medium-high heat.
Toss the halved potatoes with olive oil, salt, and pepper.
Grill the potatoes for about 15-20 minutes, turning occasionally, until tender and charred.
In a skillet, cook the bacon until crispy. Remove and set aside.
In the same skillet, cook the diced red onion until softened.
In a large mixing bowl, whisk together the apple cider vinegar, Dijon mustard, and olive oil.
Add the grilled potatoes, cooked bacon, and red onion to the bowl. Toss to coat.
Garnish with chopped fresh parsley before serving.