Big mistaking extracting files, how to "undo" it?

[Leandro Melo]

Hi.
I had a zip file which i needed to extract. 
This zip file contains a base folder in which there are a few subfolders, etc...
I opened the zip file with file roller, which naturally showed me the
base folder (the one i just mentioned). Then I set it to extract this
file under /usr/.
Specifically, this was the Eclipse project file. The zip file contains
a base folder called eclipse in which are all the subfolders and
project files.
Then i thought that file roller would extract the files to me in a way
that i would maitain the same hierarchy. So, i thought i would have
the folder /usr/eclipse and under /usr/eclipse i would have the other
subfolders and files.
The problem is that when i told it to extract, file roller simply
extract all FILES of the original zip file undre /usr/. So now i got
hundreds of file under my /usr/ directory.
Addionally, file roller didn't create any of the subfolders of the
eclipse base folder (which, as said, was not created either).
What could i do to "undo" this process? I'm very new to linux.
Is there a way i to delete files created at some specific date??? So i
just would go with this. For example: Delete all files created after
saturday 30.

Also, i could delete only all FILES from my /usr/ dir, which before
the whole thing only had subfolders. Maybe i could use rm for that,
but as i'm a linux beginner i'm not sure which comannda line options
to use. Maybe: rm -/usr/*

Well, any help is appreciated.




-- 
Leandro