1. Put the potatoes in a medium saucepan of salted water. Bring to a boil. Lower the heat; simmer until almost tender, about 5 minutes. Drain.
2. In a large nonstick or cast-iron frying pan, cook the bacon until crisp. Remove the bacon from the pan and crumble it. Pour off and reserve all but 1 tablespoon of the fat from the pan. Add the onion to the pan and cook over moderate heat, stirring frequently, until browned, about 8 minutes. Remove the onion. Wipe out the pan.
3. In the same pan, heat the reserved bacon fat and enough oil to measure 3 tablespoons over moderately high heat. Add the potatoes; let them cook, without stirring, for 6 minutes. Add 1/4 teaspoon of the salt, stir, and cook the potatoes until well browned, about 6 minutes longer. Add the onion and bacon and continue cooking until they are warm through, about 1 minute longer.
4. In a medium saucepan, heat the cream cheese, milk, Worcestershire sauce, cayenne, and the remaining 1/4 teaspoon salt over moderately low heat, stirring, until hot, about 5 minutes. Add the crab and black pepper and cook, stirring, until warm through, about 2 minutes longer. Stir the crab mixture and 2 tablespoons of the chives into the potatoes until just combined. Serve topped with the remaining 1 tablespoon chives.
Wine Recommendation: The sweetness of crab is often at its best paired with a full-bodied chardonnay, which will also be good with the bacon, potatoes, and cream cheese. Try a bottle from California or Australia.