Answer
Wa `alaykum As-Salamu waRahmatullahi wa Barakatuh.
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
In this fatwa:
Before starting Tarawih , you can say:Subhanaka Allahuma wabi hamdik, wata-baraka ismuk, wa ta’ala jad-duka wala ilaha ghayruk.
Duaa al-Istiftah means the opening supplication. It is a sunnah act of prayer and it is said after “Allahu akbar” when beginning the prayer.
With regard to your question, it is recommended for you to recite the opening duaa at the beginning of each two rakahs of tarawih prayer.
There are two duaa’s the Prophet (peace be upon him) used to say:
Allahumma ba`d bayni wa bayna khatayaya kama ba`adta bayna al-mashriqi wal-maghrib. Allahumma naqqini min khatayaya kama yunaqqa al-thawb al-abyad min al-danas. Allaahumma ighsilni min khatayaaa bil-thalji wal-maa’i wal-barad.
“O Allah, put a great distance between me and my sins, as great as the distance You have made between the East and the West. O Allah, cleanse me of sin as a white garment is cleansed from filth. O Allah, wash away my sins with snow and water and hail.” (Al-Bukhari)
And:
Subhanaka Allahuma wabi hamdik, wata-baraka ismuk, wa ta’ala jad-duka wala ilaha ghayruk.
“Glory be to you, O Allah, and all praises are due unto You, and blessed is Your name and high is Your majesty and none is worthy of worship but you.” (Sahih Al-Jami`)
Allah the Almighty knows best.
Editor’s note: This fatwa is from Ask the Scholar’s archive and was originally published at an earlier date.