I heard that it's mustahab to read from specific Surahs in quran in each of he five fardh prayers (i.e, Fajr, Dhuhr, Asr, Maghrib, and Ishaa).
What are these Surahs for each prayer? and who recommended that?
First I will have to define the word "Mufassal Surahs":
They are surahs from Al-Hujurah to the end of Quran. They're called so because they are relatively short compared to the surahs before them. So when reading them we say basmalah too often because surahs are short and finish quickly (so when starting the next one we say basmalah).
Now here we come:
For Asr and Ishaa: It's mustahab to read from (some of) the medium-Mufassal surahs, they are surahs starting with Al-Buruj to Al-Bayyinah. That's because it's mustahab to delay Asr and Ishaa (not too much, of course), so there may be no much time for a long reading, hence medium Mufassal are mustahab.
For Maghrib: It's mustahab to read from (some of) the short-Mufassal surahs, they are surahs starting with Al-Bayyinah to An-Nas (end of Quran). That's because Maghrib time is too short, so short readings are mustahab.
Where did this recommendation come from?
It came from a letter that Khalifah Omar Ibn Al-Khattab sent to Abu Musa Al-Ash'ari (may Allah be pleassed with both of them) that said:
أن إقرأ في الفجر، والظهر: بطوال المفصل، وفي العصر، والعشاء: بأوساط المفصل، وفي المغرب: بقصار المفصل.
Read in Fajr and Dhuhr [some of] long-Mufassal, and in Asr and Ishaa medium-Mufassal, and in Maghrib short-Mufassal.
Hope that's helpful.
This above information about reading a long surah in fajr is wrong as the prophet disliked the imams reading long surahs as people would not attend to prayer because of it.