How can I do a fresh install of OSX Mountain Lion onto my SSD for my Macbook?

How can I do a fresh install of OSX Mountain Lion onto my SSD for my Macbook?

So I just got a SSD for my MacBook Pro (early 2011).
My macbook is sluggish and has so much stuff that I don't use anymore and
just want to start over from scratch basically. I did a time machine
backup just in case something goes wrong. Everything that I wanted to
keep, I put on my external HDD so that I can put it back on the SSD once
OSX is installed again.
I can't directly clone everything to the SSD since my HDD has over 300GB
used and my SSD is only 120GB.
Is it possible/how can I get OSX installed on my SSD without a HDD Caddy
and no install disc since my Macbook came with it preinstalled on my HDD?
Thanks