Until Eclipse Dali gets a generic JPQL editor you can use Hibernate Tools. Hibernate Tools works with Dali and provides a HQL/JPQL query editor which uses Hibernate to execute the queries.
An alternative would be to use the JPA Query Tool [JQT], an Interactive JPA query editor and runner. It might be closer to what you’re looking for (runs as a standalone application).
Update: I removed the tool suggested for NetBeans, the project is inactive and doesn’t provide anything.