I love using buckwheat groats for cold salads — they have a unique and unexpected ultra-savory earthniess that just begs for something creamy and/or briny. I usually go with feta cheese, it's a natural pairing and since I discovered goat feta, I've been crumbling it onto just about anything. 

Smashing cucumbers helps them pickle in under an hour, it opens up their pores and crevices to the brining mixture and provides a pleasant soft-crunchy contrast. You don't want them to be obliterated, just smashed enough so that it can still be identified as a cucumber. The pickles and briny feta cheese complement the savory buckwheat and the whole business is delightfully balanced. Take it along on your picnic and see if anyone disagrees.