if(NativeProcess.isSupported)
{
var npsi:NativeProcessStartupInfo = new NativeProcessStartupInfo();
var file:File = new File("Appication to launch");
npsi.executable = file;
var args:Vector.<String> = new Vector.<String>();
args[0] = "File that is being open with application";
args[1] = "Additonal argument if any";
npsi.arguments = args;
var process:NativeProcess = new NativeProcess();
process.start(npsi);
}
This is how I did it. May be it help others. Thanks