I wish to create some files during my component after which remove them. How you can I bought the $tmp_path variable which was set through the user within the configuration.php file?
In my opinion you're searching for the [cde] function.
Take note that if you're running a mature version of PHP (before 5.2.1) you will find several comments on that page which let you know that to produce the function.
$config =&lifier JFactory::getConfig()
$tmp_path = $config->getValue('config.tmp_path')
The API documentation for Joomla! is fairly useful: JFactory::getConfig