Being short I have always loved to attack whatever my opponent is throwing at me, but it really depends on the situation.
Against a jab (especially those lazy ones used to measure distance) I attack the inside of the wrist. I don't usually think of any point specifically because there are so many in that area to choose from: L7, L8, L9, P5, P6, P7, H4, H5, H6, & H7. You’re bound to hit something.
Against a grab I go for the inside of the elbow: P3 or L5. A good shot to this area can take an opponent to the ground.
But my favorite attack to the arm is LI10. I got hit in this area so hard one time I couldn't pickup anything with that hand for two days.
Some people like to strike in the area of L1 and L2 but why? If I'm that close to him then I probably passed up a chance to hit something more vital. Of course if you’re a person with longer reach you may like that one.
But like I said it depends on the situation. Everyone seems to have their favorites.