Salafis are vigorously propagating that Allah Ta'ala is only on the Arsh and that He is not Omnipresent.

Answer

Allah Ta'ala is the uncreated, eternal, boundless Being who has no dimensions. Our minds are created and finite. Our understanding is extremely limited. It is therefore impossible for a created entity with an extremely limited sphere of comprehension to encompass in entirety The Being Who is limitless and infinite. No matter what explanation is presented to explain Allah's Presence, it will not be convincing nor can a person gain an all-embracing understanding. It will suffice for our purposes to say that place is a creation. Allah Ta'ala has created space, hence space cannot contain Him. The Arsh is a physical creation of Allah Ta'ala. A created entity cannot bear and contain the Uncreated, Eternal, Boundless Creator, Allah Azza Wa Jal. The Salafi belief leads to anthropomorphism, i.e. physical and human limbs and dimensions. Attribution of anthropomorphism to Allah Ta'ala is kufr.

The Qur'aan Majeed states in several verses, that Allah Ta'ala is everywhere. Now exactly how He is everywhere, we do not know, and no one knows. Only He knows. We believe what the Qur'aan says. We believe without probing the details which are incomprehensible to our finite created minds. Salafis are morons, hence they propagate drivel. Probing and delving into issues related to Allah's Zaat and Sifaat can culminate in kufr. Therefore, beware of this danger.