Sorry, there is none provided by the plugin.
Your only chance would be if you knew how to manipulate the database server with SQL. Then I would recomend the following workflow (If you don’t understand this, better not do it – it is your risk!):
1. Install and activate Crosswordsearch for your new subsite.
2. First enter all Project definitions by hand through the Crosswordsearch settings/projects and editors page. Use exactly the same project names. The editors for the projects may safely differ.
3. Identify the tables wp_<blog_id>_crw_crosswords both for the old and new subsite. I think <blog_id> is always numerical, you can find the match to your subsite name in table wp_blogs.
4. Copy all data from the “old” table to the “new” with something like
INSERT IGNORE INTO <new>_crw_crosswords SELECT * FROM <old>_crw_crosswords
