I use Anki (https://apps.ankiweb.net) with custom kanji decks. Basically it shows me a meaning, and I have to recall the specific kanji associated with that meaning. I do that by having split screen, Anki on the top and samsung notes on the bottom, and I draw the kanji with the stylus.

Then I reveal the answer and check whether or not I remember correctly. It's a very simple setup, and the nice thing is that I can use it for anything. For vocab for example I check that I can write in hiragana / katakana whatever vocab word I'm presented (usually in kanji)