Stir coffee and boiling water in medium bowl until coffee is dissolved. Add sugar, oil, cinnamon, sea salt, paprika and pepper; mix with wire whisk until well blended. Reserve 1/2 cup marinade for dipping sauce. Cut steak crosswise into 3-inch long by 1/2-inch wide strips. Place in large resealable plastic bag or glass dish. Pour remaining marinade over steak; turn to coat well.
Refrigerate 30 minutes or longer for extra flavor. Meanwhile, mix reserved marinade with sherry vinegar and green onion to use as a dipping sauce. Set aside until ready to serve. Remove steak from marinade. Discard any remaining marinade. Thread steak in zigzag fashion onto skewers.
Grill over medium heat 3 to 4 minutes per side or until desired doneness. Serve steak skewers with dipping sauce.