Technique tip: Let chicken sit in the refrigerator overnight uncovered on a rack so it dries the skin to make it crispier when cooked.
Swap option: Swap the harissa with whole grain mustard for a good spicy flavor and less prep work.
Heat the oven to 325°F with a rack in the lower-middle of your oven. Set a roasting rack inside a roasting pan and pour the water into the bottom (if you don't have a roasting rack, any slotted rack that keeps the bird elevated from the roasting pan will work).2.
Pat the chicken dry inside and out, then pat the herb salt evenly all over the bird. Place it on a plate with the breast side up (if you've got a wire rack, set it on top) and refrigerate, uncovered, for at least a couple of hours and preferably overnight.3.
Truss the chicken and rub the harissa all over the skin. Set it in the rack, again with the breast facing up, and roast it for about 1½ hours, until you can easily pierce the leg meat with a knife.4.
Take the pan out of the oven and bump the heat up to 500°F. Once it's come to temperature, roast the chicken for another 15 to 20 minutes, until the internal temperature of the chicken breast is 160°F (the skin will be nicely crisped up with good color, the harissa almost blackened in some areas). Let the chicken rest for 10 minutes before carving it on a rimmed platter or cutting board (it may give off a lot of juice). Cut the lime into wedges and serve them on the side along with more harissa.