How do I see who clicked through on am email send?

You need to run an email link performance report.

Email performance will show you more of how the email performed in a broad sense, while email link will show you what links are performing the best.

You can create these reports either in the program itself, or if you want a broader view in the Analytics tab. If you create it in the program, it will by default show you all emails in that program. If you do Analytics, you can select exactly which emails you want to see. 

Hope that helps!

Do you mean you want a list of which Leads are clicking? You will need a Smart List with 

Clicked Link in Email, Email IS, Link IS (optional).

Thank you both. I am very new to marketo! I tried running a Smart List earlier but had trouble with it. 
I need a step by step if possible! :) 
Thanks so much again! 

 

Smart List is:

Clicked Link in Email IS "X" (you have to choose the approved and sent email here)
you can then click on Contraint and choose

Link IS "FULL URL in EMAIL"

you do not have to do that last part unless you are looking for specific links (or if you want to say NOT CONTAINS "unsubscribe").