I agree with Craig.
I grew up in an Armenian household where shish kebab (always with lamb) was a regular meal. My dad, a chef, always cooked them on the grill. First he grilled bell peppers, onions and tomatoes and removed them to a covered bowl to steam so my mom could peel them. Then the meat skewers would go on the grill with just a thin piece of onion between each kebab.
As a kid growing up, I didn't know there was a specific reason it was done this way. After a failure or two on my own, I figured it out.
"If you want to make an apple pie from scratch, you must first create the universe." -Carl Sagan