Preheat the grill to high.
Add the potatoes to a large pot of salted boiling water and cook for 8 minutes, until just tender.
Drain the potatoes, and when cool enough to handle, cut in half lengthwise.
Toss with 2 Tablespoons olive oil. Place on the hot grill and allow to cook for 3-5 minutes, until slightly charred. Let cool slightly.
Meanwhile, make the dressing by combining the red wine vinegar, ½ cup olive oil and mustard in a bowl.
Once the potatoes have cooled slightly, toss them with the vinaigrette and the remaining ingredients. Season with additional salt + pepper, to taste.
