I know this is my first post on the forums here, but I felt that this would be the right kind of community to tell about this app. I've just released an app to help people test their knowledge of the kana systems and kanji (it covers the jouyou kanji, but there is a large overlap with the RTK list for obvious reasons).

The free version is here, and that covers all of the kana as well as the first year and a half of kanji from the jouyou kanji list (all of which are in RTK). The pay version has 2136 kanji, so it wouldn't cover all of RTK 3 but it's a nice quick way to test your memory of the kanji themselves.

It covers an English meaning as well as all of the official readings of the kanji, however I don't believe that the English meaning will align with the RTK meaning in all cases.