In Naruto what is Sasori's last name?

His full name is 'Akasuna no Sasori', which translates literally to 'Scorpion of Red Sand'. The particle 'no' in Japanese means 'of' in reverse order, so my flower (flower of mine) would be 'watashi no hana' (hana as flower and watashi as me).

Residents of Suna tend to be 'of' somewhere rather than have a surname as such (e.g. Subaku no Gaara). This is taken after the era of nights, when nobles tended to be of a place rather than have a surname (such as Sir Gareth of Naxon from Tamora Pierce's 'Song of the Lioness' quartet).

Put simply, he doesn't have one, but if you want to translate his name to English then he's 'Sasori of the Red Sand' or 'Sasori of the Desert'.