the example will show how to add a "minimize" any window in KDE.

• Goto http://www.semicomplete.com/projects/xdotool/ and download xdotool-20071230.tar.gz
• extract the tar : tar xvf xdotool-20071230.tar.gz
• cd xdotool-20071230
• make
  
• in kde open : System -> Settings -> Regional & Accessibility -> Input Actions
• click "New Action"
• In "Action Name" type minimize
• In "Action Type" select Generic
• then select "Triggers"
• Click "New"
• Select "Gesture Trigger"
• Now draw your gesture
• Next select "Actions"
• click New and select Command/URL...
• Type: xdotool key "alt+F3" && xdotool key "n" (put a link in your bin folder to the xdotool binery or use full path)
• Next select Conditions
• click New
• Select : Active Window..
• click new again
• and click OK all the way back
• your gesture should now work