Can you access table/column summaries?

For example, I want to show a warning if a column summary does not reach a certain threshold?

You cannot get at that value in merge syntax or via some API.  You have to replicate the mechanism used to create it (going through all the models to get values and doing math on them) and then use the value produced to control your page.   See this post:  http://community.skuid.com/skuid/topics/dashboard-with-categories-and-totals-that-respond-to-filter…