Spray a large grill pan with oil spray. Heat over high heat. Cook pineapple and bacon, for 2 minutes on each side or until charred and heated through. Transfer to a plate.
Meanwhile, cut each chicken breast horizontally into 2 thin fillets. Place chicken on a plate. Spray with oil, then sprinkle all over with seasoning.
Cook chicken on grill plate for 2-3 minutes on each side or until browned and cooked through.
Meanwhile, preheat grill. Toast rolls until light golden.
Place roll bases on serving plates. Smear with half the aioli, then top with lettuce, cucumber, chicken, bacon and pineapple. Smear cut-side of roll tops with remaining aioli. Sandwich burgers with roll tops. Serve.
If cajun spice isn’t your thing, try seasoning with moroccan spice mixture or lemon pepper seasoning.