Toast cumin seeds and coriander seeds in heavy small skillet over medium-low heat until seeds are lightly browned and aromatic, stirring often, about 5 minutes.
Transfer seeds to spice mill or coffee grinder and cool.
Add chili powder, sugar, salt, and peppercorns and grind finely.
Sprinkle 1 teaspoon spice rub over each side of each steak.
Place steaks on baking sheet and chill at least 30 minutes and up to 2 hours.
Heat 2 heavy large skillets over medium-high heat.
Add 1 tablespoon olive oil to each skillet.
Add 3 steaks to each skillet. Pan-fry steaks until cooked to desired doneness, about 4 minutes per side for medium-rare.