You don't. You have to make it yourself. Unless of course you want to schlep over to the place across the street and wait for 20 minutes to get your 8 pieces of lettuce, two tomato slices, a cucumber slice, a sliver of salmon, etc. But don't worry it comes topped with a heaping piece of attitude.
Better off making it yourself. Luckily, we have some nice new plates in the kitchen. Otherwise it might not look so... gourmet.