Here's the thing. This doesn't usually work, so don't get your hopes up. Still refreshes and speeds up the app. I am using Xbox smartglass as an example
Step 1: Special Wiggle Mode
Have the app you want on the third screen. Put your apps I to to special wiggle mode.( See "How to restart your device without using the power button" .
Step 2: Press the Home Button
Now hit the home button. Pretty simple.
Step 3: Darken App
Now swipe back to the third screen. The app you touched to go into special wiggle mode should have a dark tint to it *see picture*
Step 4: Open App
When you open the app, it should be "quick loaded" or refreshed!