How to Make It
In a bowl, combine the cherry tomatoes and cannellini beans. Add the lemon juice and 1 tablespoon of olive oil and toss; season with salt and pepper.
In a large skillet, heat the remaining 2 tablespoons of olive oil until shimmering. Season the steaks with salt and pepper and add them to the skillet. Cook the steaks over high heat until deeply browned and medium-rare, about 3 minutes per side. Transfer the steaks to plates.
Pour off the oil in the skillet. Add the balsamic vinegar and sugar and cook over moderate heat, shaking the pan to dissolve the sugar. Pour the vinegar sauce over the steaks. Toss the arugula with the beans and serve with the steaks.