Blend all harissa ingredients in a food processor to form a smooth paste and set aside.
Heat a griddle pan and coat steak cubes in a bowl with olive oil, salt, and pepper.
Thread the beef and red onion wedges alternately onto metal skewers.
Grill skewers for 1-2 minutes per side, basting with harissa every 30 seconds.
Squeeze lemon juice over the cooked meat and set aside.
Sauté butter, oil, onion, and garlic in a pan for two minutes until softened.
Stir in the rice, lemon zest, and lemon juice.
Add chicken stock, bring to a simmer, cover, and cook for 12-15 minutes until liquid is absorbed.
Season the rice with salt and pepper and stir in the chopped coriander.
Serve the skewers with the lemon rice and an extra dollop of harissa.