Place salt, sugar, 2 cups of cold water, garlic and bay leaf in sauce pan. Bring to a boil to dissolve the sugar and salt. Turn off heat. Add onion, orange juice and 3 cups of cold water.
Remove from stove and add to container with ice water; mix well. Cool brine mixture to 40 degrees before adding the chicken.
Rinse chicken with cold water prior to soaking in brine. Place chicken in a large enough container to hold the brine (like a small cooler with lid). When brine is cooled, pour over chicken and submerge - may need to weigh down. Keep chicken in brine for 12 - 24 hours. Remove chicken from brine and discard brine. Place chicken in a clean vessel like a sheet pan or Pyrex dish. Dry off with paper towels.
To roast on beer cans in barbeque, drink 1/2 can of beer. Rub chicken with oil, and with spices if desired. Fold wings behind chicken back. Insert beer can in cavity. Pull legs forward to allow chicken to rest comfortably on its own.
Prepare grill with heat on one side. Put a drip tray under chicken. Close lid. Rotate chicken every 20 minutes to brown all sides. When chicken is 155 degrees, open lid and move closer to the heat to crisp skin. Allow chicken to rest for 15 minutes before removing beer can.