So that's a Chinese yard long bean or also called an Asparagus bean. You generally want to harvest them at 12-16 inches long and about the diameter of a pencil, although I've definitely eaten them when I let them go longer. Generally taste just as good but they get a little tougher.

Definitely want to cook them in the shell, I normally cut them into manageable bits and then use them in stir fry or like green beans.

Your variety is probably Chinese Red Noodle Asparagus (Yardlong) Bean based on the picture.