Ed -- I'm pretty sure I know what I'm talking about.
Siduri -- No, it's a mild sweet and sour, neither clabbered nor salty. I would have said so. Limited experience (friends, one girl-friend, a couple or three restaurants), and only with soft lettuces (like butter lettuce), and once with a green bean salad.
Koukouvagia -- Same, same probably, only yours was with dill instead of onion. Left to my own devices, I would have gone more the way Ed described with creme fraiche (actually crema fresa) or sour cream, sugar, dill and a touch of horseradish -- which is fairly generic Baltic. But I can see the charm of the milk dressing with the cucumbers.
Ed -- Back to you my brother. Smitane is something entirely different. It's a veloute or brown sauce finished with sour cream. Not a great choice for a cucumber salad.
Edited by boar_d_laze - 11/7/10 at 8:31am