You can use the movement controls to move the tailpick through the lock. You must push each of the pins up in order to pick a lock.

Some locks have both a time limit and a limited amount of moves you can do in order to pick them.

The amount of moves available are normally just enough to complete picking the lock, and your time limit is visible on the upper-left side of the lock. Think fast and try to pick the lock within the available time-limit, and you'll be granted special rewards!