Let's assume I have a directory called D:\Test that contains some files starting with "Index1" followed by some other characters. If I wanted to securly delete those files I'd do this:
sdelete -p 10 D:\Test\Index1*
This would delete all files in directory D:\Test that started with "Index1". If I wanted to do this recursively I'd add the command line option -s.
Hope that helps you!