Take a day trip to Helsinki.
Finland’s capital is just 2 hours away with the ferry. A return ticket costs about 30 euros and Kauppatori (the main market square) is just a few steps away from the harbour. At the market there are lots of food stands where you can grab a local food delicacy and then head to see the main tourist attractions before heading back to Tallinn again in the evening. Another pin on your map is always welcome, especially when it comes to another nation’s capital at such a short distance. So definitely do that. How?