Planning a Mileage Run to Helsinki

I have my second and final mileage run to get to American Airlines Executive Platinum status coming up this weekend (leaving less than 3 days after coming back from my round-the-world trip). I’m headed to Helsinki, flying AA to JFK and then Finnair to HEL. My ticket was ~$850, and the routing provides about 13,400 EQMs.

To be honest, I haven’t spent much time researching what I should do in Helsinki. I’m staying at the Radisson Blu Plaza Hotel, as I finally got my US Bank Club Carlson credit card three weeks after my supposedly “instant approval” (my sign-up bonus points won’t show up in time, so I got a friend status match to Club Carlson elite status so that he could transfer the necessary points to me so I could book my room). Because I have the credit card, the last night on award stays is free, so it was only 44k Club Carlson points for two nights at the hotel.

I’ve been looking at places to eat, and Helsinki has some restaurants that I’m really interested in trying (e.g. Olo, Luomo), but I didn’t want to make a reservation for Saturday night in case I’m severely jetlagged and not in the mood to eat a multi-course feast. I also was somewhat shortsighted in booking my trip to overlap on a Sunday, as it seems like most restaurants are closed on Sundays. Does anyone have any suggestions on good places to eat, particularly places to eat on Sundays, or have any experience walking in without reservations to some of the nicer restaurants in Helsinki?

I am also looking for suggestions on things to do. I’ll probably try to hit up a sauna (in the same spirit as my trips to a Turkish bath and getting a Chinese massage) and Market Square, and a friend recommended taking a tour of Suomenlinna. Any things in Helsinki that I shouldn’t miss?