For the marinade:
Add the onion, red peppers, garlic, harissa, tomato paste and salt to a blender or food processor and blend until the onion is very finely minced.
With the motor running on high, slowly stream in the canola oil and blend until emulsified.
For the skewers:
Toss the steak with the salt and thread onto skewers.
Pour the marinade into a large container that will fit the skewers. Add the skewers and turn to coat the meat. Cover and refrigerate for at least 3 hours or up to overnight.
Remove the skewers from the marinade and wipe the excess marinade from the meat.
Preheat the broiler with a rack set 3 inches from the heating element.
Place the kebabs on a wire rack set inside a rimmed baking sheet and broil until slightly charred on the outside, 3 to 5 minutes per side.
Rotate the kebabs and cook for another 3 to 5 minutes per side.
Remove from the broiler and de-skewer on to a plate. Top with the green onion and enjoy!
