The men's 10km sprint was twice postponed in Bulgaria due to heavy fog. However Christiansen made the most of clearer conditions on Monday to take the win.
The Norwegian shot clear to take gold in 25:34.4, 17.5s ahead of Benedikt Doll of Germany while Ukraine's Artem Pryma finished third, another 30 seconds adrift.
And, rather than bemoan the continued postponements of the sprint, Christiansen, who finished 18th in the 20km individual, actually admitted that it played into his favour in Bansko.
"We arrived here only two days before the individual and during the individual our form was really, really bad, like we had a rock in our bottom," said Christiansen.
"The deep pressure here made it feel like we were on 1800 meters so the stopping of the races was a big advantage.
"I was lucky during the standing because there was almost no wind. But it really is not that difficult, just aim at the black."
Meanwhile Hojnisz also shot clean for gold in the women's 10km pursuit ahead of German duo Franziska Preuss and Karolin Horchler.
And, despite a lack of fog, Hojnisz admitted conditions were still not perfect in Bansko with wind this time causing problems for athletes.
"The conditions were very hard, especially at the shooting range. When we had the zeroing, the wind was from the right," said Hojnisz.
"During my second shooting, there was no more wind. I did not know what to do but I turned five clicks and then shot zero again."
The European Championships in Bansko will continue on Tuesday with the men's 12.5km pursuit and the women's 4x6km relay.