According to the Teiid Salesforce source code, nothing was changed there regarding DELETE operations. They still work not using bulk logic. The Teiid Salesforce connector can perform DELETE operations without bulk logic but these are kind of soft-delete operations which means that the deleted records are put in the bin on the Salesforce side and they are not removed entirely from the system. It requires manual operation of emptyRecycleBin() using the web interface. In Addition, the DELETE operation is comparatively slow for use cases with several hundred records to delete.
We tried the Salesforce DataLoader tool and noticed that the deletion of records is up to 10 times faster compared to the current deletion in Teiid.
The SFDC bulk api can perform both hard and soft deletes. It would have to be driven by configuration or hint which one you actually wanted to perform.
It looks like it should be possible to implement similar to the bulk query - adding a batch based upon the soql delete query string - with the additional handling of the batch job.