In a small bowl, combine cumin, coriander, 2 teaspoons coarse salt, and 1/2 teaspoon pepper. Rub steaks all over with spice mixture.
Heat a large skillet over medium-high; add meat (if crowded, cook in two batches). Cook 2 to 4 minutes per side for medium-rare. Transfer to a cutting board. Tent steaks with aluminum foil, and let rest at least 5 minutes.
Meanwhile, reduce heat to medium; add bell peppers, onion, and chiles; season with salt and pepper. Cook, stirring occasionally, until crisp-tender, 8 to 10 minutes. Add lime juice, and stir, scraping up browned bits in skillet.
Stack tortillas, and wrap in a damp paper towel or kitchen towel. Microwave on high 1 minute. Thinly slice steaks crosswise, and serve with tortillas, peppers, onion, and chiles, along with sour cream and lime wedges.