What is the ruling on istinja' after urination, and is it done with water and soap or with water only?
Istinja' from urine and stool is obligatory. It is permissible to perform istinja' with water alone, or with toilet paper alone. The best way is with toilet paper then water. If one wishes to suffice with one of them, then water is better. And Allah the Almighty knows best.
What is the ruling on swearing on the Holy Quran and breaking that oath?
It is impermissible to swear on the Holy Quran in vain, and it is also impermissible to subject it to such an act since breaking the oath after swearing on the Quran entails an expiation.
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.
Some online stores offer a discount on a customer's first purchase — what is the ruling on creating a new account each time a customer makes a purchase in order to obtain that discount?
All praise is due to Allah, and peace and blessings be upon our master the Messenger of Allah ﷺ.
It is obligatory upon a Muslim to uphold honesty in both his words and his actions. Allah the Almighty says {what means}: "O you who have believed, do not betray Allah and the Messenger or betray your trusts while you know." [Al-Anfāl/ 27] And He says {what means}: "O you who have believed, fear Allah and be with the truthful." [Al-Tawbah/ 119]. And the Messenger of Allah ﷺ said: "Whoever deceives us is not of us." (Reported by al-Bukhārī.)
As for creating a new account for the same buyer, the terms and conditions of the website must be observed and respected. If doing so violates those terms, it is not permissible. And Allah the Almighty knows best.