If I pay contractor cash, can I still claim it as expense

Yes, but he must declare it as income. So be sure to get his SSN or EIN, and issue him a 1099-NEC.

[edited] The IRS rule is that you must issue a 1099-NEC to a contractor to whom you pay $600 or more in the course of your trade or business.  The IRS also says "you are engaged in a trade or business if you
operate for gain or profit." 

https://www.irs.gov/pub/irs-pdf/i1099mec.pdf

You must enter the contractor's SSN or EIN on the 1099-NEC.  If the contractor prefers not to divulge his SSN, he can obtain an EIN online here (there's no charge):

https://www.irs.gov/businesses/small-businesses-self-employed/apply-for-an-employer-identification-number-ein-online

You must issue a Form 1099-NEC (not 1099-MISC) to any contractor to whom you pay a total of $600 or more for the year. You must, of course, also file the 1099-NEC with the IRS. As TomD8 said, Form 1099-NEC is only for payments from your business (which includes a rental property), not for a contractor who did work for you personally, such as work on your own home. Form 1099-MISC is no longer used for payments to contractors.

If the total that you paid a contractor during the year is less than $600, you do not have to issue a 1099-NEC. You can still claim it as an expense of your rental property. Your accounting records for the rental should show the payment.

In order to issue a 1099-NEC you must have the contractor's tax ID number (EIN or SSN). To avoid problems, you should always get a contractor's tax ID number before the contractor does any work for your rental, even if you don't expect to pay $600 or more, in case you end up using the contractor for additional work later in the year.

Q. Do I need to give him 1099? If so how? Do I need to get his SSN?

A. Simple answer: no. 

It became a little fuzzy under the new 2018 tax law. Landlords are, generally, still not require to issue 1099 forms to service providers.

References: http://www.forbes.com/sites/irswatch/2013/03/06/should-landlords-be-filing-1099s-for-service-providers/

Q. If I pay him with cash, I can still claim this as my rental maintenance right?

A. Simple answer: yes. But, your burden of proof in case of an audit will be a little tougher.  In addition to a receipt, it might be helpful if you bank statement showed a withdrawal for that amount in that time frame.