Not directly. You have to create a list of keys in a backing bean and use that as the value for the dataTable.

@In HashMap myHashMap;

@Factory("keyList")
List<String> keyListFactory()
{
 List<String> keys = new ArrayList<String>();
 keys.addAll(myHashMap.keySet());
 return keys;

}

in the xml:

<rich:dataTable value="#{keyList}" var="key" >
 <rich:column>#{key}</rich:column>
 <rich:column>#{myHashMap[key}</rich:column>
</rich:dataTable>

Interestingly it looks like this functionality could be added to richfaces by simply copying the seam SetDataModel class and adding a few lines to SequenceDataAdaptor.java in ajax4jsf. I will file a JIRA.