Rub the steaks with cumin, pepper, and salt, and let them rest; this allows the flavors to penetrate. The spice rub also helps the steaks develop a tasty charred crust.
Cook the cumin and peppercorns in a dry small skillet over medium-high heat, stirring often, until fragrant and slightly toasted, 1 to 2 minutes; let cool. Finely grind in a spice grinder; stir into salt.
Rub 3/4 teaspoon spice mixture over each side of each steak. Let steaks stand at room temperature 30 minutes.
Preheat a grill to medium-high (if using a charcoal grill, coals are ready when you can hold your hand 5 inches above grill for just 3 to 4 seconds). Grill steaks, turning once, about 4 minutes per side for medium-rare. Serve with salsa.
Use any leftover spices on vegetables.