Is it safe to walk from Zuni cafe (Franklin St) to war memorial opera house Grove st at night?

Frankly, not really. If you look at the crime websites such as crimereports.com, you will see that there have been literally dozens of assaults in that area of the city in the last six months. Although you will probably be alright on a one-off sort of outing, you are putting yourself at an increased chance of getting assaulted. This is especially true if you are a gal or only with gal friends. I would call a cab rather than take unnecessary chances. If you do decide to do it, stick to Van Ness and Market which are better lit and high traffic.

Good luck either way.