1 flank steak, about 1 1/2 lb.
2 large or 4 medium tomatoes, halved crosswise and seeded
2 Tbs. olive oil, plus more for brushing
Salt and freshly ground pepper, to taste
1 Tbs. herbes de Provence
1/2 cup crumbled fresh goat cheese
2 tsp. red wine vinegar
2 cups mixed salad greens