preheat grill to 350-400 (Med-high) heat.

place potatoes in a single layer in center of a large piece of aluminum foil;drizzle with oil; sprinkle with salt and pepper. seal aluminum foil to make one large packet.

grill potatoes in foil packet, covered with grill lid, 15 mln on each side. remove from grill, carefully open packet using tongs let cool 5 mln.

whisk together mayonnaise and next 4 ingredients in a large bowl add potatoes, tossing gently to coat. stir in onion, blue cheese and bacon.