For the tomatoes: Preheat the oven to 400 degrees F.
On a large rimmed baking sheet, combine the cherry tomatoes, cocktail tomatoes and Roma or Campari tomatoes. Drizzle with the oil and scatter the torn basil over the top. Season with the salt and toss well to coat. Roast until the tomatoes are lightly browned and beginning to give off their juices, 30 to 35 minutes. Allow to cool slightly.
For the salad: Arrange the tomatoes on a large platter. Tear the burrata over the top. Scatter the arugula and basil over the top and drizzle with the oil. Finish with the flake salt and black pepper, if desired.