Not sure about the setup in Helsinki, but last year in Boston skaters were everywhere. I don't recall official meet and greets, but you'll see them in the concourse, leaving the venue, at local shops and restaurants or at some of the exhibition booths during the competition itself.
I would also recommend during the competition, if you're sitting up in the rafters to come down to the main concourse during ice resurfacing and breaks. You're bound to run into many skaters who are there to watch the other competitions and cheer for their teammates.
Also, if Ice Network has a broadcast desk, find out where it is. Last year, the Shibs were at the table following their competition and signed some autographs. If you attend practices, most skaters will sign autographs after they are done with the practice session. Last year after Ladies practice the day of the FS, Ashley, Gracie and Mirai signed many autographs and took selfies with fans.
ETA: It's probably to best approach them after they have finished competing, they may be more relaxed and willing to chat. Each skater is different, but as long as you are polite, most are happy to chat briefly.
Also, I didn't do this last year, but if you know which hotel the skaters are staying at fans staked out the bars or the lobby the evenings and got to meet many skaters.