"What do you like about...?"
How do you express "What do you like about XY?" in Mandarin? I specifically mean this kind of wording, as in a dialogue that goes:
"I like Sichuan food."
"What do you like about it?"
"It's so spicy!"

I do not mean: "Why do you like it?"Perhaps I ought to clarify what I mean by "What do you like about it?". It is not supposed to mean "Why do you like it?", but rather: "What aspect about it do you like?", or "What is the reason for which you like it?".
I know it's a fine line, but it's definitely not the same.

Question

"What do you like about...?"
How do you express "What do you like about XY?" in Mandarin? I specifically mean this kind of wording, as in a dialogue that goes:
 "I like Sichuan food."
"What do you like about it?"
"It's so spicy!"

I do not mean: "Why do you like it?"Perhaps I ought to clarify what I mean by "What do you like about it?". It is not supposed to mean "Why do you like it?", but rather: "What aspect about it do you like?", or "What is the reason for which you like it?". 
I know it's a fine line, but it's definitely not the same.

Answer

這樣看你about後面接的是什麼，翻譯上會不一樣。
譬如：
What do you like about Germany? （你喜歡德國的哪裡/的什麼/的什麼地方？）這裡的哪裡不是指地方，是指特點。
What do you like about me?（你喜歡我哪點？）

你這段話的What do you like about it?翻成「你喜歡川菜的什麼？」會比較妥當，可是回答回的是「超辣啊！」那硬要翻的話What do you like about it?這句翻成「為什麼喜歡川菜？」會比較符合回答耶。
"I like Sichuan food."
"What do you like about it?"
"It's so spicy!"

Answer

"What aspect about it do you like?", or "What is the reason for which you like it?
你喜歡川菜的哪裡/的哪點/的什麼特色？or為什麼喜歡川菜？

總歸來說你都可以用「你喜歡川菜的哪裡/的哪點/的什麼特色？」表示What do you like about it?
根據不同情境有很多翻法，畢竟這兩種語言是不同語系，文化背景布一樣，不是所有句子都能逐字翻出來，就像英文沒有德文的Sie這個用法一樣。

Answer

你喜欢xxx的哪个方面？你喜欢xxx的什么？

Answer

“你觉得川菜怎么样”