Dissolve Silver Oxide
Well, $\ce{Ag2O}$ is just a basic oxide. As such, it would dissolve in suitable acids ($\ce{HNO3}$ would do), but I guess that's not quite what you want. Well, some metal oxides ($\ce{ZnO}$, for instance) are amphoteric and thus would dissolve in $\ce{KOH}$ as well, via formation of hydroxo complexes. Sadly, this is not the case with $\ce{Ag2O}$. Then we must resort to some specific complex which would be stable in alkaline media.

Indeed, there is such complex: $\ce{Ag(NH3)2+}$, the active component of Tollens' reagent, which is prepared by interaction of $\ce{Ag2O}$ with aqueous ammonia, like I said. If you are actually going to do it, read the page carefully, including the "Safety" section, or at least don't make that solution by gallons and don't leave it unattended for years. Also, note that it is normally made using freshly prepared $\ce{Ag2O}$; dry reagent off the shelf would likely dissolve as well, only much slower.