I don't have a Mac but in my Linux Install it is like this:
/home/username/didnapper2/1.0.3/Didnapper 2/www/save
So look for a www folder and for a save folder within in your game data. The files are named global.rpgsave, config.rpgsave and file#.rpgsave (replace # with number shown in the game). So a system-wide filesearch for these files could also help you find them (given they use the same filenames on Mac and Linux).
Hope that helps.