Salateira is a Ukrainian chain of, as they call themselves, healthy salad restaurants. Usually, when people hear about salad as the only option for lunch, they have some doubts, because it seems not enough for lunch. However, their portions are really big, and you should be really really hungry to order some soup along with the salad.
There is also an option to change the salad in the dish to pasta. Their menu contains salads with pre-chosen ingredients, however you could swap or change them as you like. This is a great place to get a bite as a lunch option (however, during lunch hours, waiting time could be 15-20 mins or so).
Similar restaurants are located across the city. Usually, big malls have one. And since it is a chain, all of them have some nice things. For example, you could take a free apple when you make your order. There is also free fresh water with refills (that is why I never actually order a drink there).
They have a system that you say your name during the order, and they call you by it later. You could do a funny thing and come up with some unusual or fake name. It is very interesting to hear it later spoken out loud from the speakers, just don’t forget what you told and you won’t miss your order :).