The only somewhat laborious part of this dish is cutting the tomatoes in half, but if you don’t, the sauce won’t cling to them and they’ll burst in your mouth in a way that dilutes the vinaigrette. Be sure to buy olives that have been already pitted. The tuna is used raw, but it is partially cooked by the heat of the pasta. When shopping, be sure to tell your fishmonger that you’ll be serving the tuna a little on the raw side.