Line a baking sheet with parchment or wax paper and set aside. Peel the mandarin oranges.
In a microwave safe bowl or with the help of a double boiler, melt chocolate chips and add shortening or coconut oil, if desired. Adding shortening or coconut oil is optional – it helps make the chocolate super smooth and easier to work with. Using only melted chocolate will work fine as well.
Dip each slice halfway into the melted chocolate and place on prepared baking sheet. Sprinkle with salt and repeat until all slices are evenly coated and sprinkled with salt. Refrigerate overnight or until chocolate and mandarin are both firm. Serve cold.