I don't think so. I have never heard of it used in this way either. There is a word munchy, but it does not mean "tasty". It means something that can be munched (also "munchable"), or the quality of being munchable. In this sense it is "originally and chiefly US", says the OED. E.g.:I've never heard "munchy" used for something tasty. May be it's BE.
Munch is really very near chew in sense. If you can chew it, you can munch it. Which excludes all liquids or near-liquids.That's funny, I had never thought of the 'munch' to refer to a certain type of food. I would have said you can munch anything. To me personally, 'munch' is either a less formal or 'correct' synonym for 'eat', or it could refer to a way of eating...maybe kind of a more relaxed way of eating. However, I do not base this on any evidence other than my personal understanding of it.
The dictionary.com definition says it all for me:'Munchy,' I believe, is derived from a sound that you may make when you munch on something. Now would you call liquids, which you don't munch on, munchy? How about something like watermelon --- could it be a munchy watermelon?
So, no, a liquid can't be munchy. I suppose a water melon might be - I don't know, I never eat them (can't bear the texture).–adjective Also, munchie.
1. (of food) a. crunchy or chewy.
b. Informal . for snacking: munchy foods like popcorn and cookies.
2. munchies, Informal . food suitable or meant for snacking: Munchies were served before dinner.
3. the munchies, Slang . hunger, esp. a craving for sweets or snacks: suffering from the munchies.
Based on the Random House Dictionary, © Random House, Inc. 2010.