This is a really interesting cucumber. (It is actually a type of melon.)
Last year, a friend of ours gave us one of these cucumbers from his garden for seed saving. He had let it grow to a considerable size/length, of course, to ensure plump and viable seeds. It has a light green, slightly ribbed, thin skin. We did taste it, though, and it was crisp, sweet and juicy, even though it was 'grown up'.
Here it is in my garden. These are two plants that are now growing nicely. They are flowering profusely.
Have a closer look! Aren't they just the cutest baby cucumbers? Grow, cucumber, grow!