In NFC interactor for Windows Phone, go to the “tag reader” page and tag a tag to read its NDEF message.

Now, tap and hold the parsed message on the screen. After a moment, the context menu will appear, which allows viewing the raw message contents. Tap this option and the NDEF message will be shown as a hex string.

Windows Phone only supports reading the NDEF message; it does not allow apps to read outside of the message area (= the rest of the tag memory area).