Perhaps called this way because of its shape, kòn means horn in Haitian Creole, this mango is eaten by poking a hole in the skin and sucking the juice of the fruit out.[:fr]
Cette mangue tient sans doute son nom de sa forme, le mot kòn veut dire corne en créole haïtien. On la mange en perçant un petit trou juste assez gros pour laisser passer le jus du fruit que l’on presse. [:]
How can I get some of those mangos?
In Haiti, everywhere when they’re in season around May-June. Outside of Haiti, not sure. Probably in ethnic or latino stores.