Simple but useful tool!
Kana trainer I made for myself once upon a time.
You will get one or more characters, and you must type the same string into the text box. You can give the answer in hiragana, katagana, or a latin translation. For example if you get "かんあ", you can type either "kana", "かんあ", or "カンア" as the answer.
Click the "+" button for options.
If you open the hiragana/katagana character lists, you can disable/enable which characters can appear for you. This way you can start with only a few characters so you won't get overwhelmed.