How can you find out if a guy is on Tinder?

According to their website, Tinder allows you to search your matches but it does not employ a general search feature. You can search through your list of matches by pressing the message button icon on the main screen of the app, then pull down the screen until the search bar shows up and type in their first name.

How do you find someone on Tinder again?

Use the Rewind feature to bring their profile back by tapping the yellow arrow icon on the main screen. Only Tinder subscribers can take back their last SWIPE of choice (Like, Nope, Super Like). To subscribe, open Tinder > tap the profile icon > Settings > Get Tinder Plus, Tinder Gold or Tinder Platinum.