Heat the grill to medium high (about 375°F to 425°F). Meanwhile, rub the steaks on all sides with the oil, generously season with salt and pepper, and let come to room temperature while the grill is heating.
Grill the steaks uncovered for 5 minutes per side for medium. Remove from the grill and let rest for 10 minutes. Cut into large dice and set aside.
For the salad:
Heat the oven to 350°F. In a medium mixing bowl, toss the potatoes with the olive oil and season with salt and pepper. Place on a baking sheet and bake until the potatoes are knife tender, about 18 to 20 minutes. Remove from the oven and let cool to room temperature.
Place the reserved steak, bell pepper, parsley, celery leaves, and scallions in a large, nonreactive mixing bowl. Halve the baked potatoes and add to the bowl. Toss with the vinaigrette and season with salt and pepper as needed.
Beverage pairing:Castello di Farnetella, Chianti Colli Senesi, Italy. A fun dish to pair, since the acidity of the tomatoes and vinegar makes a big, rich red—a classic pairing for steak—impossible. Instead, the verve and bright herbal and tart cherry flavors of this traditionally made Sangiovese are perfect.