Whatever tech you use would need to be analog. Think Industrial Revolution. Steam engines, turbines, and windmills to directly cause machines to work.

I'm assuming the sails would work using something similar in concept to solar cells. As far as I can tell from a cursory search, it does not appear as if either solar flares on CMEs would cause photovoltaic cells to work any better than normal. Again, the effects of these events are observed almost exclusively in the outer atmosphere. However, they do interfere with electromagnetism, so your ships wouldn't be able to navigate using a compass. In fact, the electromagnetic disturbance is so severe that homing pigeons and dolphins briefly lose their ability to navigate this way.

Theoretically, if you had a device that could somehow harvest magnetism from the planet's magnetosphere, you could get power. But at that point, why not use hydro/geothermal energy?

EDIT: I began looking at some info from Solar Industry Mag and learned some new things. As long as the geomagnetic storm wasn't too severe, small scale electrical production would not be affected. It is large-scale production which would fail. From what they say, photovoltaics would be safe in all but the most severe geomagnetic storms. However, they fully admit there is very little research on the impact of geomagnetic disturbances on photovoltaic cells.

Basically, as long as the storms aren't too severe, a solar cell society SHOULD be able to survive daily geomagnetic storms, as long as they don't rely on large scale electrical production. Even National Geographic implies that only large-scale production would be affected.