Place the potatoes in a large pot and cover with cold water. Place over high heat and bring to a boil. Cook potatoes until fork tender but with still a little give in the middle, about 15-20 minutes. Let potatoes cool for about 10 minutes and then cut in half. Brush each side with a small amount of olive oil and season with salt and pepper.
Turn the grill on medium heat and place potatoes on, cut side down. Grill potatoes for about ten minutes, until you get some good grill marks.
Place all of the dressing ingredients into the blender and blend for 10-20 seconds. Place grilled potatoes on a plate and pour dressing over potatoes or use dressing as a dip to dip potatoes in.