The Italian vocal quartet Quartetto Cetra performing "Crapa Pelada" ("Bald Head").
The 1945 recording appeared in the Breaking Bad episode "Full Measure" (Season 3's finale).
Now, who on that show has a bald head? Like Walter White himself, nothing the show's writers do is an accident; surely this particular song is not there without greater significance than to highlight Gale Boetticher's goofiness. That scene is below.