Both are correct and is just slang for someone who requires their area to be spotless. Where I. Live, the U.S., "neat freak" is more commonly used. Both mean the same.

"Clean freak" and "neat freak" are both acceptable - I would use "clean freak" in this situation as it refers more to germs (you can also use the phrase "germaphobe" in this situation) - "neat freak" is more about ensuring things are tidy and in order.

Chris gave a good distinction between the two. In your sentence you mixed past tense (found) and present tense (asks). If you wanted to use found you would have to say "would ask". If you want to use asks, you would use "finds". He is a neat freak. If he finds even teeny, tiny spots or stains on the floors, walls, furniture or cars, he asks his house cleaners to wipe them up immediately. Teeny, tiny.. such specific adjectives work better with 'even', as opposed to 'any'. If you want to use any, I would say "If he finds any spots or stains". Any spots and even tiny spots mean the same thing, but "even" emphasizes that everything will be well scrutinized and nothing will be missed. "not just any spots or stains, but even the teeniest, tiniest spots".