Where can you get sanskrit essays in sanskrit language?

You have not mentioned the purpose for which you need these Sanskrit Essays. To my knowledge as of now there are no ready-to-use essays on subjects of popular interest available on the net. Textbooks on Sanskrit Essays are available from many publishers from Varanasi. For eg., Chaukhambha Sanskrit Sansthan or Chaukhambha Sanskrit Pustakalaya.

If you want on a specific subject you may please message me on my Message board with your EmailID.