Interesting quote from St. Cyril:
“When thou goest to receive communion go not with thy wrists extended, nor with thy fingers separated, but placing thy left hand as a throne for thy right, which is to receive so great a King, and in the hollow of the palm receive the body of Christ, saying, Amen.”
(St. Cyril of Jerusalem: “Fifth Mystagogical Catechesis”, 21: PG 33. col 1125 (c. 350 AD) as cited by the Quintsext Synod of Trullo Canon 101 (c. 692 AD)
With all due respect to St. Cyril, he does not set liturgical disciplines. Moreover, what “may” have been true in his day may not be today. The sainthood of a person does not give him authority over current liturgical disciplines.
If you want to know the liturgical norms of today, read the magisterial norms of today. For example, MEMORIALE DOMINI: Instruction on the Manner of Distributing Holy Communion. This document was issued to try to contain the abuses caused by communion in the hand (but ultimately failed to do so):
ewtn.com/library/CURIA/CDWMEMOR.HTM
Yet more regarding the St. Cyril of Jerusalem canard:
A more rigorous study of available evidence from Church history and
from writings of the Fathers does not support the assertion that Communion
in the hand was a universal practice which was gradually supplanted and
eventually replaced by the practice of Communion on the tongue. Rather,
facts seem to point to a different conclusion: Pope St. Leo the Great
(440-461) is an early witness of the traditional practice. In his comments
on the sixth chapter of St. John’s Gospel he speaks of Communion in the
mouth as the current usage: “One receives in the mouth what one believes by
faith.” (2) The Pope does not speak as if he were introducing a novelty, but
as if this were a well established thing.
A century and a half later Pope St. Gregory the Great (died in 604) is
another witness. In his dialogues he relates how Pope St. Agapitus performed
a miracle during Mass, after having placed the Body of the Lord into
someone’s mouth.
catholic-pages.com/mass/inhand.asp