Step 1Place the orange juice in a saucepan over medium-high heat. Cook until the liquid is reduced by a third. Stir in the brown sugar and continue cooking, stirring constantly, until the sugar dissolves and the mixture is slightly syrupy.
Step 2Remove the mixture from the heat and stir in the chipotle and liqueur. Heat the oven to 350 degrees.
Step 3Cut the thick skin and excess fat off the ham, leaving about one-fourth inch of fat. Score in a crosshatch pattern. Place the ham on a rack in a shallow roasting pan. Brush some of the glaze evenly over the top. Place in the oven and pour water into the pan to a depth of about 1 inch. Bake 10 minutes per pound, basting every 15 minutes with the glaze.
Step 4Transfer the ham to a carving board and let it rest 15 minutes before slicing.
Step 5Return the remaining glaze to a saucepan, add the orange zest and bring to a boil and cook 1 minute. Serve on the side as a sauce.