1.
Stir salt together with sugar, onion powder, garlic powder, cayenne pepper, paprika, and ground mustard in a bowl. Rub under and on top of the chicken skin.
2.
Wrap chicken in plastic wrap and chill in refrigerator for 1 hour.
3.
Preheat grill for indirect heat and set up a drip pan.
4.
Drink (or otherwise remove) about 1/3 of the beer. Use a sharp implement to poke a few extra holes in the top of the can. Then, without spilling the beer, set the chicken on top of the beer can so that the empty body cavity is filled with the can.
5.
Set the chicken on the grill, standing up, over the drip pan. Close lid. Cook for about 1 1/2 hours, until chicken reaches an internal temperature of 180 degrees F.
6.
Let the chicken rest off the grill for 10 minutes, then use pliers or heat-protective gloves to take the can out of the chicken. Carve and serve.