Cook bacon in a skillet for 8 to 10 minutes until crisp and drain. Pour off the fat and brown beef in the skillet for 8 to 10 minutes until it reaches 160°F, then season with salt and pepper and drain. Spread beef in a shallow dish and refrigerate promptly to cool.
Meanwhile, boil pasta shells in water with the tablespoon salt until fully tender. Drain, rinse briefly under cool water and drain thoroughly.
Mix mayonnaise, barbecue sauce and vinegar. Fold through pasta with cooled beef, kidney beans, corn, cheddar and red onion.
Add crisp bacon just before serving. Keep the dressed salad refrigerated until needed.
Stir gently before portioning and refrigerate leftovers within 2 hours.