I sent a letter to a foreign country.
Why don't you put up the letter from Kim Jong Il for online auction? I think somebody would buy it.
I’m going to write a very heated letter to Coca-Cola and ask why there is so much sugar in their products.
A hand paper being a letter seems kind of strange, but think of it this way:
Paper that you can fit in your hand? That's good for a letter. Also, you could write a letter on your hand if you want, though it would hurt a lot to chop off your hand and send it (imagine doing this).
The reading is double kun'yomi (body parts tend to make kanji in words change to a kun'yomi reading). Both kanji in this word had you learn that reading right from the start, though, so you should be able to read this word. Just watch out for the rendaku making it がみ, not かみ.