I like my kimchi mild.

(Does 'mild' modify kimchi? What is the opposite of 'mild'?)

3 answers

Yes, it modifies kimchi.

The opposite of mild is spicy or hot, something like that.
1. I like my kimchi which is mild.
2. I like mild kimchi.

(Thank you. What about the sentences? Are both the same?)
Yes, they are correct, and they're interchangeable, too.