I've successfully use an application specific URL scheme for this. Let's assume your URL scheme is "kuiperstimestamp".
The tag then should contain a URL like:
kuiperstimestamp://ts/20130506T034536.293
You then create an intent filter for your service that includes a data
element:
<intent-filter>
<action android:name="android.nfc.action.TAG_DISCOVERED" />
<category android:name="android.intent.category.DEFAULT" />
<data android:scheme="kuiperstimestamp" />
</intent-filter>
Since the intent filter is rather specific, you don't get the app selection dialog (unless another app or service has the same specific intent filter which is unlikely).
This approach is less Android specific than using an AAR.