Civi AJAX API Search by "AND"ing 2 Tags
I don't think you can do this with one api call.

Not optimal but you could do a postprocess in place of the // do something when the result comes.

Better, you could create your own api call in a custom extension - see https://wiki.civicrm.org/confluence/display/CRMDOC/Create+a+Module+Extension#CreateaModuleExtension-AddanAPIfunction