Yeah.. avoid the candy canes, or anything like it. My ducks love peas and mealworms too, as well as watermelon, cucumber, and their own cooked eggs. Limit any treats you do give, as their main food source should always be their feed.
I always say “treat treat” when I give any of my ducks a treat, so when they hear the words, they come running - you could do that or some variation of it. I sit on the ground and throw treats towards them, saying “treat treat” when I throw. Once they’re comfortable eating treats near you, you can move to them eating out of your hand. Just hold your hand still, near the ground, and let them come to you.
Move slow, talk to them calmly to get them used to your voice. Be patient. You’ve got this
Also, here’s a much broader, fantastic list of treats you can give
https://www.backyardchickens.com/threads/the-ultimate-list-of-duck-treats-and-supplements.242460/