There are two different ways to vent the sink. One, you run a high loop before running the drain line through the floor and tie in with existing vents, or tww - use a special vent under the sink, provided drain lines have adequate venting elsewhere. Here's a link to an article that explains:

Here is a link that might be useful: Island sink vent

Most AHJs will not allow an island vent in anything except an island.
Any wall can be used for a conventional vent and that is what you will likely be required to use unless Studor vents (AAVs) are allowed under the code in your area.

Studor valves are not allowed in California, but you can run vent lines on the outside of the house if needed in most counties, since there is little chance of freezing. You can also run the vent pipe sideways to an existing vent in some cases. You need to check with your local building department to see what they prefer.

I personally would open the walls all the way to the roof, even if it's 3 stories, rather than look at that pipe for the rest of the time I'm in the house. Dry wall is cheap and easy to repair.

Depending upon the horizontal distance from the riser to the vented branch or main drain that the horizontal line discharges into it may not be necessary to install a vent.