I used the following method in asp.net to retrieve all caches (then I remove some caches based on the regular expression pattern).
IDictionaryEnumerator caches = HttpContext.Current.Cache.GetEnumerator();
I found GetObjects* but they are only available in Windows Sever AppFabric.
Is there any equivalent in Windows Azure AppFabric Caching?
In its current manifestation, no. You will need to know which keys there are/you need to get and set appropriate timeouts if you don't want to keep track of your cache items. Also missing are regions, tags and notifications which (for many use-cases) would offer a perfect workaround/efficient alternative to getting all cache-items or keys.
If you are unhappy with the state of azure caching you could put your frustration here or there.