Are apps that I have deleted from my device still saved on my cloud? And if so how can I delete them to free up storage space?

You can see if any of the apps are using your iCloud space by going to Settings>iCloud>Storage & Backup>Manage Storage, under Documents & Data. (Documents & Data are the only thing about apps store in your iCloud account.) If one is listed there, tap it, tap Edit, then tap Delete All to remove the app's documents and data from your account.