We could also see this as a MediaWiki core issue.

https://commons.wikimedia.org/w/index.php?title=en:meta:wikipedia:de:commons:wiktionary:fr:wikisource:en:wikipedia:zh:wikidata:wikipedia:en:User:Jc86035&oldid=176158522&action=delete works, but then the form is redirected to the whole sites and lands to en.

Okay, I've a procedure to do that with tools accessible to any Commons administrator.

1. Get the page id

On http://quarry.wmflabs.org/ or from the tools bastion, run the following SQL command:

SELECT page_id
FROM page
WHERE page_namespace = 0 AND page_title = 'en:meta:wikipedia:de:commons:wiktionary:fr:wikisource:en:wikipedia:zh:wikidata:wikipedia:en:User:Jc86035';

Here, the answer is 44329577.

?action=info will redirect to en., so no luck here to get the page id.

2. Use the API

The API allows to delete a page by identifier.

The easiest way is to use https://commons.wikimedia.org/wiki/Special:ApiSandbox.

With the exception it had the bad idea to use Main Page as default value.

Choose delete in action, don't fill a title but the page id. Beware, it's a scrollable field. If you use your touchpad or mouse wheel to scroll, it will increase or decrease the value.

Alternatively, we can generate a token and use an URL like /w/api.php?action=delete&format=json&pageid=44329577&reason=Accidental+creation&token=... but it must be posted, GET requests won't work.

3. Check the result

API will confirm the operation:

{
    "delete": {
        "title": "en:meta:wikipedia:de:commons:wiktionary:fr:wikisource:en:wikipedia:zh:wikidata:wikipedia:en:User:Jc86035",
        "reason": "Accidental creation. At the request of [[User:FDMS|FDMS]].",
        "logid": 156956014
    }
}

Log should say:

2016-04-08T14:35:42 Dereckson (talk | contribs | block) deleted page en:meta:wikipedia:de:commons:wiktionary:fr:wikisource:en:wikipedia:zh:wikidata:wikipedia:en:User:Jc86035 (Accidental creation. At the request of FDMS.)

See also: T87645: Existing pages without ability to reach and obviously wrong namespace