In a medium bowl combine the guacamole ingredients and stir with a fork until thoroughly combined; cover the surface with plastic wrap until ready to use.
In a blender or food processor finely chop the garlic and cilantro. Add the remaining marinade ingredients. Process until smooth.
Put the flank steak in one medium bowl and the chicken thighs in another. Add half the marinade to the steak and half to the chicken and turn to coat all sides evenly. Cover and refrigerate for 1 to 2 hours.
Prepare the grill for direct cooking over medium heat (180° to 230°C).
Prepare the grill for cooking over medium heat (200°C).
Brush the cooking grates clean. Lightly coat the bell peppers and onions on both sides with oil, and then grill over direct medium heat, with the lid closed, until tender, turning once. The bell peppers will take 6 to 8 minutes, and the onions will take 8 to 10 minutes. Remove from the grill and cut the bell peppers and onions into 8-millimeter strips.
Brush the cooking grates clean. Lightly coat the bell peppers and onions on both sides with oil, and then grill over medium heat, with the lid closed, until tender, turning once. The bell peppers will take 6 to 8 minutes, and the onions will take 8 to 10 minutes. Remove from the grill and cut the bell peppers and onions into 8-millimeter strips.
Remove the steak and chicken from their bowls, discard the marinade, and then grill over direct medium heat, with the lid closed, until the steak is medium rare and the chicken thighs are brown on the surface and no longer pink in the middle, 8 to 10 minutes, turning once. Remove from the grill and let rest for 2 to 3 minutes. Evenly divide the tortillas into two foil packets and grill over direct medium heat to warm them, 2 to 3 minutes, turning once.
Remove the steak and chicken from their bowls, discard the marinade, and then grill over medium heat, with the lid closed, until the steak is medium rare and the chicken thighs are brown on the surface and no longer pink in the middle, 8 to 10 minutes, turning once. Remove from the grill and let rest for 2 to 3 minutes. Evenly divide the tortillas into two foil packets and grill over medium heat to warm them, 2 to 3 minutes, turning once.
Cut the steak in half lengthwise. Cut the steak and chicken across the grain into 6-millimeter slices. Place the tortillas, steak, chicken, peppers, onions, guacamole, and salsa in separate serving dishes. Let each person make their own fajita by placing the fillings down the center of each tortilla and adding hot sauce. Serve warm.
