Preheat oven to 400 degrees F. Soak 24 wooden toothpicks in warm water. Lightly coat a large, rimmed baking sheet with cooking spray.
In a medium bowl, toss pineapple with lime zest and lime juice, salt, and pepper.
Skewer each toothpick with scallion, bacon, scallop, and pineapple and stand up on the baking sheet. Bake about 12 minutes until the scallops and bacon are cooked through.