The old version of numbers had a "hide column or row" feature. I could right click a column and the "hide" option appeared on the same window as "add/delete" and "merge." However with the 3.2 update I no longer see that option. Is it somewhere else?
I'm using Numbers 3.5 on Yosemite. In this version I can click the tiny arrow on the row number (e.g.. 1-20) or the column letter (e.g.. A-P) and this yields a menu (hover the row number or column letter to see the small arrow). The choices "Hide row" and "Hide column" are in those respective menus.
According to your description, it appears that these "hide" features have been moved to their respective row/column header menus.