Would "Cos'e il tuo nome: also work?

You can also say "come si chiama?" it is more polite version if you don't know other man.

By literal translations, I believe:

"Come ti chiami?" = "How are you called?" "Cos'e il tuo nome?" = "What is your name?"

I think Duo just choose a poor translation here.

I also reported this sentence because it popped up in http://www.duolingo.com/word_practice/it/si/Pronoun but it doesn't use "si".

I guess one can say "come tu ti chiami" then. Is it a right guess ?

i think that it should be added as a correct answer "Qual è il tuo nome?"

One thing I find curious is Italians apparently ask HOW you are called rather than WHAT you are called, which is most common in English.