Are the parts touched by a hand contaminated with semen in the toilet considered impure, even though water reaches them, and do they become pure after drying?

Firstly: Masturbation is forbidden (haram) and has many harms.

Secondly: The preponderant opinion (rajih) according to us is that semen is pure (tahir), and therefore the toilet does not become impure (najis) by coming into contact with semen.

Thirdly: According to the view that semen is impure (najis), the spot touched by your hand can be purified by drenching it with pure water (ma' tahur) if you are certain or mostly certain that the impurity has been removed.