You can use just about any tomatoes you like best for this recipe. Big, juicy tomatoes are the best, though – we really love using heirloom tomatoes when they're available. You can use cherry or grape tomatoes; cut those into quarters instead of dicing them. The only variety that I find does not work well is San Marzano-style (aka sauce tomatoes). Their texture makes them great for making tomato sauce, but not so great for enjoying raw in recipes like this.