Tuna salad — rillettes de thon in French — is a nice cold accompaniment to fresh summer tomatoes. This salad is made of thon germon (a.k.a. thon blanc, called "albacore" in North America), shallot, cornichons, capers, mayonnaise, and dried oregano. You can add some of the water that the tuna is packed in to thin the mayonnaise slightly and add more tuna flavor.
Butter lettuce and diced zucchini, along with green olives, are good garnishes.
At the last minute, we decided that some hard-boiled eggs (œufs durs) would be a good addition. And some fresh parsley that we have growing in pots on the front terrace. There's something old-fashioned-looking about tomatoes stuffed this way, but they tasted pretty good.