Now I know that in TT, you have to serve the ball from behind the table and above the playing surface. My question is, can I stand sideways to the Table and make the serve provided my ball is still outside the table as shown in the image below?
As the ITTF rules state :
From the start of service until it is struck, the ball shall be above the level of the playing surface and behind the server's end line, and it shall not be hidden from the receiver by the server or his or her doubles partner or by anything they wear or carry.
There's no mention of where your body has to be positioned during that part of the game, so parts of your body can be over the playing area, or as you are asking along the side of the area. The only thing that matters is the position of the ball itself.
If you need more info about this, I encourage you to check out this link : http://www.allabouttabletennis.com/official-table-tennis-rules.html