In a mixing bowl, stir together olive oil, lime juice, orange juice, apple cider vinegar, honey, red onion, cilantro, garlic, jalapeno, chili powder, cumin, paprika and season mixture with salt and pepper to taste. Place flank steak in a baking dish and pour marinade over steak. Cover with plastic wrap and allow to marinate in refrigerator 2 - 5 hours, rotating once halfway through marinating.
Brush a grill lightly with oil and heat grill to medium-high heat. Remove steak from refrigerator. Lift steak and allow excess marinade and bits to run off, season with salt and pepper to taste and transfer to grill. Cook about 5 minutes per side, or until desired doneness (could be more or less depending on how thick your steak is and if you like it medium rare or more well done).
Transfer to a plate or clean baking dish, cover with foil and allow to rest 5 minutes. Cut into thin strips and serve over warm tortilla shells along with desired toppings. Serve immediately.
Warm the tortillas on a dry skillet before assembling your tacos (they're less likely to break when warm).
The toppings I've listed are all optional and are not included in the nutrition estimate. Make your tacos however you'd like!