Things you should pay attention to:
1) огурец - огурца;
2) бутерброд is not a sandwich actually, this word is taken from the German language and it means "one piece of bread + something up", we have the word for sandwich and... this is сэндвич;
3) салат - this is how we call everything which has green leaves and which we add to a salad, yes, so салат has two meanings:
a) salad;
b) vegetable with green leaves.