Combine the juices, oil, rum, shallots, garlic, oregano, cloves, and cumin in a medium bowl. Whisk together.

Rinse steak, pat dry, and trim off any excess fat. Place steak in a Ziploc bag and pour marinade in, turning and maneuvering steak to coat it. Seal bag and remove the air. Place in a glass dish and marinate in the refrigerator overnight or for at least 12 hours, turning every few hours to make sure the marinade is evenly distributed.

Remove steak from marinade, pat dry with paper towels and season both sides with salt and pepper. Reserve the marinade.

Spray a grill pan with olive oil spray and heat over medium high heat. Add steak and sear, about 5 to 7 minutes. Turn with tongs and cook 2 more minutes. Pour marinade into the pan and begin to reduce. Remove steak after 2 more minutes for rare, give it 1 more minute for medium rare, etc. Remove steak when it looks less cooked in the center than you would like, since it continues cooking while it is resting.

Allow steak to rest for 10 minutes before slicing. Continue cooking marinade until it boils and thickens, scraping up the bits on the bottom of the pan with a wooden spatula. do not let all the liquid evaporate. Remove from heat.

Slice steak against the grain perpendicular to the striations running through it into 1/4 inch thick slices. Serve with citrus marinade reduction on top.