Martinianus’s name day is February 13, the feast of Martinian.
Churches that follow the Old (Julian) Calendar keep the same feast on February 26 of the civil calendar. See everything commemorated on February 13.
The saint behind the name

Martinian
February 13, Venerable, Μαρτινιανός
St. Martinian was a hermit of the region of Caesarea in Palestine, who took up the ascetic life as a young man and dwelt for many years in the desert in prayer and fasting. Tradition tells of the fierce struggles he endured against temptation, and of the lengths to which he went to preserve his purity, fleeing at last to a bare rock in the sea and then wandering from place to place with no home but Christ.
Name days: Martinian, Martinianus
Also celebrating on February 13
These names share the feast, many of them other forms of the same name:
What to say on a name day
The Greek wish is Χρόνια Πολλά (Chronia Polla), “many years.” A call or a short message on the day is what people remember. See name day wishes you can send and what a name day is.