A popular vegetable in India, this tiny gourd can now be found in Indian markets in California and elsewhere. Here it is always sold green, looking very much like a tiny cucumber, but in India it is also sometimes used in it's scarlet red mature stage.
Tindora can be eaten raw and are a lot more crunchy than cucumbers, or they may be cooked as a side dish or may be pickled. When pickled they are sometimes called "gherkin" but are easy to tell from the real Gherkin and from cucumber gherkins by their smooth skin. Typically they are between 2-1/2 and 3-1/4 inches long, 3/4 to 7/8 inch diameter and weigh around 5/8 ounce.
More on Cucumbers.
In parts of India folklore holds that eating red ripe tindora causes brain death but they are eaten that way in other parts by people who don't seem to suffer premature dementia. In California they are always sold in the much more popular green stage. If you want red ones you need to grow your own vines, which I understand is very easy to do - they grow like weeds and are in fact listed as weeds in Texas and Florida and "noxious weeds" in Hawaii. They are said to be quite sour when fully ripe.
Aside from being cooked alone they can be combined with other vegetables or can be used in salads as cucumber would be, or just serve them whole as refreshing munchies.