Like in the U.S., unusual fruits start to crop up at the grocery store during certain times of the year... These are actually some our friend brought back from Guadaloupe but I've seen them in the stores and never thought to try one... They are called Sharons, and I'd never eaten one. (Have I been under a rock?)
By checking online I learned that these are actually native to China. The waxy skin is similar to a tomato's but thicker and easy to peel . The orange flesh is sweet but more firm, like a soft apple. There are no seeds. The taste is very mild, much less flavorful than citrus fruits.