Quote Originally Posted by xXHoax View Post
(Non-native Russian here, apply light salt)

fresh is modifying the "picked". A word modifying a verb or an adjective is an adverb, which in Russian will almost always be formed with the short-neuter form of the relating adjective.
Right, except that the adverb "свеже" (fresh) merges with the next adjective (свежесорванный). You can also use "только что".

Quote Originally Posted by xXHoax View Post

'is' is very often omitted entirely in the present tense.

The Russian sentence will look like: "[NOUN PHRASE (nominative)] [NOUN PHRASE (nominative)]" and it will be understood that you are making an "A is B" sentence. (Technically speaking this is because you have two nominative nouns, meaning what would theoretically be two subjects of the sentence. Since the two 'subjects' are not followed by any other specified verb [conjugated in the plural], it is assumed that the only verb it could be is "to be")

You are allowed to add a long dash, if you feel it will clarify that the sentence is conveying "A is B." You will probably have an urge to do this more than a Russian would, since they are used to the omission. Looks like "A — B."

есть is possible, though you don't see it terribly often. In such situations есть functions as both either "is" or "are," since the plural form 'суть' is largely archaic. Probably, erase these from your mind for use in this type of case, because you'll have have a strong urge to use it often, despite it's rare use.

In more complicated situations, "is" can manifest as words like "заключаться" ("Проблема заключается в том, что...") or "являться" ("Главным препятствием здесь является невнимание к этой проблеме." --one noun takes the subject, and the other takes instrumental., in the form "A (nom.) is B (instr.)". You'll notice that Russians often put the instrumental part first, which can really stretch the English mind.), among others, I'm sure.
The common way to say that is to use the word "это" (optional).

Свежесорванная кукуруза - [это] ...

Quote Originally Posted by xXHoax View Post
"the quintessential summer foods", as said above, this noun phrase will be in the genitive.
I'm not much help on vocab or word choice. Seems alright to me.
Neither "пища" nor "еда" has plural genitive. So you have to rephrase that. For example:

Свежесорванная кукуруза - одно из классических блюд летней кухни (one of classic dishes of summer cuisine)