I don't think you can initiate a crawl, but you can use the Crawl Test tool to see how it looks.
http://pro.seomoz.org/tools/crawl-test
Ready to crawl? Our Crawl Test helps you zero in on duplicate content, summarize redirect locations, learn rel-canonical values, and more. Enter any subdomain below and we'll crawl up to 3,000 linked-to pages. In the next few days you’ll receive an email containing a CSV report with the results.