Cauna made five appearances for Brendan Rodgers' side after joining on loan from Skonto Riga in January and conceders he would be interested in a return.
He told UEFA.com: "The atmosphere at matches in England is unforgettable. The four months at Watford were the best of my career and I really want to go back.
"It seemed at times that these guys were just flying over the pitch.
"If you start thinking after receiving a ball, you have lost it. You don't have any time to make decisions. Initially training made my head spin but I got used to it and now I'm stronger, both mentally and physically."