Bring 1 inch of water to a boil in a large saucepan fitted with a steamer basket. Add cauliflower, cover and steam until tender, about 4 minutes.
Meanwhile, remove skin and white pith from lemons with a sharp knife. Working over a bowl, cut segments from the membranes. Coarsely chop the segments and transfer to a serving bowl. Squeeze juice from the lemon peel and membranes and add 1 tablespoon of the juice to the bowl with the segments.
Add oil, shallot, water, thyme, salt and pepper to the serving bowl. Stir to combine. Add the cauliflower and toss to coat. Sprinkle with olives. Serve warm or at room temperature.
1 vegetable, 1 fat