In a small bowl, whisk together mayonnaise, lime juice, sugar, salt, and pepper. Add cabbages, carrot, and green onion, stirring to combine. Cover and refrigerate until ready to use. (Slaw can be made earlier in the day.)
Using a 2¼-inch round cutter, cut 16 rounds from frozen bread slice, discarding scraps. Spread one side of each bread round with softened butter.
In a large nonstick sauté pan, toast bread rounds over high heat until crisp and brown, approximately 1 minute per side.
Ruffle 1 slice chicken on buttered side of each bread round, and top with slaw.
Garnish with green onion, if desired. Serve immediately.
Recipe by TeaTime Magazine at https://teatimemagazine.com/buffalo-chicken-and-slaw-canapes-recipe/