Learn Farsi: سؤالِ تو خوب است.

In Farsi, possession is formed using the Ezafe (a short 'e' sound). You link the noun سؤال (question) to the pronoun تو (you) with this sound, literally making it "question of you". You don't need a separate word for "your".

What is the little symbol above the و in سؤال?

That is a hamza (ؤ). It tells you to make a glottal stop, which is a tiny catch in your throat like the pause in the middle of the English word "uh-oh". Here, it cleanly separates the first vowel sound from the long "â" in سؤال (so'âl).

Since we are learning about کدام (which), how would I ask "Which question is good?" to get this sentence as an answer?

You simply place کدام before the singular noun, and you do not use an Ezafe. "Which question is good?" would be کدام سؤال خوب است؟ (kodâm so'âl xub ast?). Notice how کدام سؤال doesn't use the connecting 'e' sound, unlike the possessive سؤالِ تو.

Would I hear است pronounced fully like this in everyday conversation?

In formal settings or news broadcasts, yes. But in casual spoken Farsi, the verb است (is) usually merges with the word before it and turns into an 'e' sound. A native speaker would almost always say سؤالِ تو خوبه (so'âl-e to xub-e) instead.