Washing the hands and face with soap during Wudhu is not prescribed by Islamic law, in fact, it is something excessive, and it has been authentically reported from the Prophet Sallallaahu alayhi wasallam that he said:
هَلَكَ الْمُتَنَطِّعُوْنَ، هَلَكَ الْمُتَنَطِّعُوْنَ
"May the Mutanatti'oon be destroyed, may the Mutanatti'oon be destroyed." [Muslim no.2670, Abu Dawud no.4607 and Ahmad 1:386.]
He said it three times. Yes, if it is confirmed that there is some dirt on the hands which cannot be removed except by using soap or some other cleaning agent, then there is no objection to using it. However, if it is a habit, then using soap is considered an excessive act and an innovation, and it should not be used.
 Note what follows is not from the speech of the Shaykh, it is added for the benefit of the English reader:
Imaam an-Nawawee describes al-Mutanatti'oon in his explanation to Sahih Muslim as:
"المتعمقون الغالون المجاوزون الحدود في أقوالهم وأفعالهم"
“[They are] those who delve too deeply [into things], the extreme ones, those who go beyond bounds in regards to their speech and their actions.”