These are heavily modified versions of GTA: Vice City Stories or GTA: Liberty City Stories . Talented modders change the textures, player skins (to look like CJ), vehicles, maps, and user interface to replicate the look and feel of San Andreas.
Never download files that require you to install an .apk file or complete surveys before downloading. Legitimate game files should only ever extract into an .iso or .cso format.
A: No, Rockstar Games never released GTA: San Andreas for the PSP. The versions you play on PPSSPP are fan-made modifications.