What is the ruling of Islamic Law on kissing while fasting?
All praise is due to Allah, and peace and blessings be upon our master the Messenger of Allah ﷺ.
It is prohibitively disliked (makrūh taḥrīman) for a husband to engage in foreplay with or kiss his wife during the daylight hours of Ramaḍān if doing so stirs his desire. If pre-seminal fluid (madhī) is released as a result, the fast is not invalidated; however, if seminal fluid (manī) is released, the fast is broken.
Imām al-Khaṭīb al-Sharbīnī, may Allah have mercy upon him, stated: "It is prohibitively disliked to kiss — whether on the mouth or elsewhere — for one whose desire is stirred, whether man or woman, to the extent that he fears it may lead to intercourse or ejaculation. Embracing, touching, and similar acts without a barrier carry the same ruling as kissing in this regard, because such acts expose the act of worship to being corrupted — and as the two Ṣaḥīḥs record: 'Whoever circles around a protected boundary is liable to fall into it.'"
He further added: "It is preferable for one whose desire is not stirred — even if he is a young man — to refrain from such acts as well, so as to close the door entirely. For he may believe his desire has not been aroused when in fact it has. Moreover, it is Sunnah for the fasting person to abstain from all desires without exception." — Summarised with minor adaptation from [Mughnī al-Muḥtāj]. And Allah the Almighty knows best.
I can`t afford to get married, what should I do to curb my sexual drives?
You should offer a lot of voluntary fasting, keep busy with useful and permissible acts and make supplication to Allah, The Exalted.
What is permissible for the person who wants to ask for a woman`s hand in marriage to see from her body?
He is permitted to see her hands and face only, but if he wants to see more, then he has to send a woman that he trusts to do so.
What is the ruling on wiping the white area behind the ears instead of wiping the head?
The obligation in ablution is to wipe some of the head; it is not a condition to wipe all of it. Wiping the white area behind the ears suffices for that. And Allah the almighty knows best.