In a large saucepan, combine sugar, orange juice, and agar agar powder. Stir well and, if needed, add a few drops of food coloring.

Stir the mixture CONSTANTLY and cook on medium-high heat until it comes to a rolling boil. Then lower the heat to medium-low and continue until the boiling mixture is thick, for about 4-5 minutes.

Pour the mixture into a 10x10-inch rimmed pan lined with parchment paper. Distribute the mixture evenly in the pan and chill for two hours in the fridge.

Cover about 1/2 inch at one of the edges with parchment paper and sprinkle powdered sugar on top of the rest.

Dip a sharp knife in warm water and use it to loosen the jelly around the edges and cut it into two blocks by running the knife across the middle.

Roll each piece tightly into a log, being careful not to get any powdered sugar on the end where the paper was, or it will not stick at the end. Use the end to stick the roll together tightly.

Cut the orange candy roll into 1/2-inch pieces and serve.