Heat broiler with rack 4 inches from heat. In a small bowl, combine chili powder, coriander, sugar, oregano, 1 tablespoon coarse salt, and 1/2 teaspoon pepper. Coat steaks evenly on both sides with oil, then spice mixture, patting to adhere.
Place half the steaks on a rimmed baking sheet or broiler pan. Broil, without turning, until medium-rare, 5 to 8 minutes, depending on thickness. Transfer to a large platter, and cover with aluminum foil; let rest 10 minutes. Meanwhile, broil remaining steaks; transfer to a large plate, let cool to room temperature, then cover and refrigerate to use later for Steak Sandwich with Peppers.
Remove foil and divide steaks among four serving plates. Drizzle with any accumulated juices, and serve with Romaine-Heart Salad.