Ziyarat Ashura (Arabic: زیارة عاشوراء) is a Shia salutatory prayer to Husayn ibn Ali and the martyrs of the Battle of Karbala. The prayer is part of the liturgy used in pilgrimages to the shrine of Husayn in Karbala.
It is highly recommended to perform these two Rak'ats of Salah of Ziyarat but not obligatory.
The narration in Kaamil Al-Ziyarah is more authentic. Nevertheless it is good to recite السلام عليك يا خيرة الله وابن خيرته with intention of Qurbatan Elallah Ta'alaa.
It is permissible to prostrate on a clay on which something is written, though it is much better to prostrate on plain clay ( Torbah) or Mohr or Sajdagah.