First of all, great job on making the switch to a more eco and animal friendly lifestyle - the planet will thank you for it!
I agree with the other girls, I think your body is capable of cleansing itself however if you want to cleanse then go for it.
I think naturally as a vegan you will (or def. should be) consuming a very high portion of veggies, fruits, whole grains and healthy non-animal proteins so your body will feel better in no time. You could kinda call it a lifestyle cleanse