QuickSiri helps you open Siri all the time in fullscreen mode

  The personal assistant Siri in iOS 5 opens automatically in a small border that we have displayed at the bottom of the screen. When we ask him a question, he closes everything that is visible above him and is displayed on the entire screen of our iDevice. QuickSiri is a tweak released last night in Cydia that forces Siri to open on the entire screen every time we activate it. Practically, now Siri will occupy the entire screen of the iDevice and when we ask it a question it will display it directly without opening its interface.

  QuickSiri is available for free in Cydia's ModMyi repo. QuickSiri works with any iDevices that have Siri installed.