How does Munchkin identify users without a form submission?

My question is around how, or if Munchkin code can identify individual leads who have engaged with a CTA but have not submitted a Marketo form?

I have multiple sales reps who want to include a graphic/promotion in the signature of their personal Outlook email offering a demo of our training software. So basically I need to create a Smart Campaign that identifies each lead who "clicks" on the offer and sends an alert to the corresponding rep.

In this scenario, each rep will have a graphic promotion embedded in the signature of their email offering a demo, which will then direct the recipient to a custom landing page that is built on Wordpress. 

Ideally, I could create a form that collects each lead's information and sends an alert based on their existing contact information in Marketo, or the information they just submitted via a Marketo form.  

But is this the only accurate way for Marketo to track individual users, or does Munchkin identify users who are already known in our Marketo/Salesforce database simply from landing on the page?  

And what about for users who are unknown in Marketo, or might be returning users and have the Munchkin cookie embedded in their browser, but have no personal information synced to Marketo?

What if the user is known in Marketo but has cleared their cookie history, will Munchkin still be able to identify them?

Keep in mind that this promotion is a graphic embedded in our sales reps Outlook email signature which directs them to a Wordpress landing page with Munchkin embedded in the theme.