1. In a dry medium skillet, lightly toast cumin seeds over low heat for 4 to 5 minutes or until fragrant.
2. For marinade, transfer toasted cumin to a food processor. Add lime juice, jalapeños, black pepper, garlic and salt. Cover and process until cumin seeds are finely ground. Add cilantro and olive oil; cover and process until smooth.
3. Place steaks in a large resealable plastic bag. Pour marinade over steaks; seal bag. Turn bag to evenly coat steaks with marinade. Refrigerate for 8 to 24 hours, turning bag occasionally.
4. Remove steaks from the refrigerator 30 minutes before grilling. Preheat grill with a greased grill grate for direct cooking over high heat (450°F).
5. Remove steaks from marinade, discard marinade. Grill for 7 to 9 minutes or until steaks reach 130°F, turning halfway through. Transfer steaks to a cutting board; loosely cover with foil and let rest for 5 minutes. Thinly slice steaks across the grain to serve.

*Note: Chile peppers contain volatile oils that can burn skin and eyes. When working with serrano and jalapeño peppers, wear protective gloves.