Core the tomatoes, slice them in half horizontally, and flick out most of the seeds and juice with a fingertip. Then cut the tomatoes into 1-inch chunks and put them in a large serving bowl.
In a small bowl, combine the vinegar and honey.
In a 10- or 12-inch sauté pan over medium heat, cook the pancetta in two or three batches until crisp and golden, 3 to 5 minutes per batch. Remove the pancetta from the pan, drain on paper towels, roughly chop, and keep warm (or set aside at room temperature if making ahead). Depending on the pancetta, there might be lots of fat in the pan or there might be none. Pour the fat into a dish, measure out 2 Tbs., and return it to the pan, discarding the rest. Add 5 Tbs. of the olive oil (or more to compensate if you didn’t get enough pancetta fat) for a total of 7 Tbs. fat in the pan. Set aside.
When you’re ready to serve, bring a large pot of salted water to a boil. Put the beans in the boiling water and cook until just tender, about 5 minutes. Drain the beans and spread on paper towels or a dishtowel to dry briefly. Put the warm beans in the bowl with the tomatoes and set it at the back of the stovetop to keep warm. Put the pancetta in a warm oven for a few minutes while you finish the dressing.
Return the pan with the reserved pancetta fat and oil to medium heat. When the fat is warm, whisk in the vinegar-honey mixture, turn the heat to high, and whisk until the mixture boils and emulsifies. Immediately pour the hot dressing over the vegetables in the bowl. Toss, season with salt and pepper, and add the chives. Sprinkle the chopped pancetta over the salad and scatter the cheese over the top; toss gently. Serve immediately.