How could I swiftly and legally evict them from a property of mine, even if I have no legitimate reason other than my need to save money on my diet?

With that said there must be a swift way to analyze 2-4 unit multi-families. 

With few exceptions, it's landlords not acting swiftly and correctly within the law that makes CA evictions takes months instead of weeks.  

Be fair, firm and swift when dealing with tenants who violate the terms of a rental agreement.

I commend @Matthew Paul for taking swift and decisive action to protect his interests.

It was swift and brutal."

Tenants need a swift kick in the rear sometimes to understand that you are serious about your job (which is growing and keeping your business safe) and those notices followed by someone (a repair man, handyman, yourself) stopping by to assure the appropriate remedy has been fulfilled.  

If the tenant violates a term of the rental agreement, then address the matter swiftly.

It is important to be firm, fair and swift in addressing the matter.Oh, also... serve a "Notice to Enter" and inspect the entire unit as soon as possible!

@Atul Mohlajee Always best to nip this type of thing in the bud with swift enforcement of the terms of your rental agreement.