Kraft, the maker of Jell-O, has a recipe for mandarin orange Jell-O salad on KraftRecipes.com. The website also has a couple of recipes for mandarin orange molds.
The Kraft recipe calls for one 11-ounce can of mandarin oranges, one 3-ounce package of orange Jell-O, 1 tablespoon of fresh lemon juice and 6 ounces of cream cheese. First drain the oranges, making sure to keep the juice from the can. After mixing the Jell-O with 1 cup of boiling water until the Jell-O is dissolved, stir in 3/4 cup of the juice from the mandarin oranges and the lemon juice. Pour 1 1/4 cups of that mixture in a loaf pan sprayed with cooking spray and place in the refrigerator until it is set but not firm. Gradually add the remaining Jell-O mixture to the cream cheese in a medium-sized bowl; whisk the cream cheese and Jell-O mixture after each addition. Then, add the drained oranges. Spread this creamy layer on top of the Jell-O layer and refrigerate it until firm, about four hours.
The KraftRecipes.com also has directions for unmolding a Jell-O dessert or salad. Dip the pan in warm water for about 15 seconds so that you can pull the gelatin gently from the edges of the pan. Place a serving plate or platter, moistened with water, on top of the pan, and turn the pan and plate over, holding them together. The Jell-O mold should slip easily out of the pan once you shake it gently.