Melothria scabra

Melothria scabra, commonly known as the cucamelon, Mexican miniature watermelon, Mexican sour cucumber, Mexican sour gherkin, mouse melon, or pepquinos, is a species of flowering plant in the cucurbit family grown for its edible fruit. Its native range spans Mexico to Venezuela. Fruits are about the size of grapes and taste like cucumbers with a tinge of sourness. It may have been eaten by indigenous peoples before the European colonization of the Americas began....read more on Wikipedia.