Arrange the beefsteak tomato slices, flesh side up, in a single layer on a platter or on individual plates. Scatter the cherry tomatoes over them. Season them evenly with the sugar, Maldon salt, and black pepper. Drain the onions, pat them dry with a kitchen towel, and sprinkle them over the tomatoes. Drizzle with the dressing and sprinkle with the tarragon. Finish with the warm bacon. Serve immediately.