Oranges with Olives

At Chez Panisse on the 6th, I had an starting course called 'Martin's blood oranges with green olives and watercress, and marash pepper'. It was very good - one thing that Alice Waters cooking does well is incorporating different textures as well as palate flavors, i.e. bitter, sweet, salty, and sour. In theory,this app had it all - olives for salty, oranges met both the sweet and sour taste bud requirements, and watercress a slight bitterness. I say in theory, only because while the potential was there for everyone to see, the putting together of it all was far from balanced. The water cress was a little too mild (maybe it needed more pepper to boost its own slight peppery flavor) and there weren't enough olives to counter the sweet sour of the blood oranges. But I LOVED the idea, so I am trying to work out my own version.

Could I use a premade olive tapenade and just plain oranges? What about bitterness...?