Answered: For upcoming v1.6.3: Please change the menu navigation, so that "Ask a question" is first.

As of 1.8.6, the order can be changed in: /qa-include/app/page.php

Move this block:

_{// Only the 'level' permission error prevents the menu option being shown - others reported on /qa-include/pages/ask.php}

_{if (qa_opt('nav_ask') && qa_user_maximum_permit_error('permit_post_q') != 'level') {}

_{$qa_content'navigation']'main']'ask'] = array(}

_{'url' => qa_path_html('ask', (qa_using_categories() && strlen($lastcategoryid)) ? array('cat' => $lastcategoryid) : null),}

_{'label' => qa_lang_html('main/nav_ask'),}

_);

_}

above 

_{if (qa_opt('nav_activity')) {....}