Oil the grill grates of your grill with paper towels lightly coated with grapeseed or canola oil. Preheat one side of the grill on high and one side on low for 10-15 minutes.

Rinse the whole chicken and pat it dry with paper towels, then place the chicken on a cutting board. Using a pair of kitchen shears, butterfly the chicken by cutting out the backbone of the chicken. Press down on the chicken to flatten it.

Transfer the chicken to a baking dish.

Mix the harissa with juice from ½ of the lemon, ½ of the orange and the olive oil in a small bowl. Slather the harissa mixture on the front and back of the chicken.

Cover 2 bricks or pavers with aluminum foil, with the dull side on the outside.

Tuck wings under the breast. Place the chicken, breast side down, over indirect heat (the side of grill set to low). Set the bricks on top of the chicken. Close the grill cover and cook for 20-25 minutes. Carefully remove the bricks and flip chicken. Top the chicken again with the bricks and cook until an instant read thermometer inserted into the thickest part of thigh reads 155°, anywhere from 10-20 minutes depending on your grill's maximum temperatures. Move the chicken to the hotter part of the grill and replace the bricks. Cook for 5-10 more minutes to crisp up the chicken skin.

Grill the remaining halves of the orange and lemon.

Serve chicken with a squeeze of the orange and lemon and more harissa if desired.