You can use what GetTempPath returns concatenated with a Guid to ensure uniqueness of the directory. You can create a Guid using UuidCreate or CoCreateGuid Function.

To delete recursively the directory, there is an example here in pure C: How to remove directory recursively? based on FindFirstFile, FindNextFile, DeleteFile and RemoveDirectory.

There is also SHFileOperation but it's more heavyweight and is based on the Windows Shell functions, and the Shell DLLs are not always wanted, especially if you're writing server code.