Prepare 3 round 9" pans by lining the bottoms with 9" circles of wax paper.
Spray the wax paper with Pam and then sprinkle with flour.
Mix the cake mix, lime jello, oil, eggs, orange juice, and water together for 2-3 minutes at medium speed.
Pour an equal amount of the batter into each of the 3 prepared pans.
Bake at 350 for 25 minutes.
Glaze
While the cakes are baking, knead two limes against a hard surface to loosen the juice inside of them. Cut each lime in half.
Squeeze 1/4 c fresh lime juice into a small bowl.
Pour 1/4 c bottled lime juice into the bowl with the fresh juice.
Mix in 4 Tbsp of confectioners sugar. When the cakes come out of the oven, and while they are still warm, use a spoon to drizzle the glaze mixture onto the entire surface of each cake.
Icing
Mix the margarine and cream cheese together. Gradually mix in confectioners sugar.
Add the vanilla and mix until smooth.
If you want green icing, just add a few drops of green food coloring.
Notes
This cake may also be baked in a 9x13 pan. Spray and flour the pan and bake at 350 for 32-35 minutes.