At the restaurant, the lamb is served with cilantro-corn mashed potatoes.
Preheat oven to 425°F. Oil heavy large baking sheet. Toss garlic with 2 teaspoons corn oil in small bowl. Transfer to baking sheet. Roast 6 minutes. Add pumpkin seeds; toss to coat. Roast until seeds and garlic are golden brown, stirring once, about 5 minutes longer. Transfer to rack; cool. Maintain oven temperature.
Transfer garlic-pumpkin seed mixture to processor. Grind until coarse puree forms. Mix in remaining 2 teaspoons corn oil.
Using long sharp knife and starting at 1 end of lamb, cut slit in center of each lamb rack half, extending slit to opposite end of lamb. Insert handle of wooden spoon into slit, enlarging slit to 3/4-inch-diameter hole. Combine feta, sun-dried tomatoes, olives and cilantro in large bowl. Fill hole in each lamb rack with feta mixture, dividing equally.
Transfer lamb to prepared baking sheet. Spread mustard over rounded side of lamb; press 1/4 of pumpkin seed coating into mustard on each lamb rack half.
Roast lamb until meat thermometer inserted near center of lamb registers 135°F. for medium-rare, about 25 minutes. Let lamb rest 15 minutes.
Spoon 1/3 cup Chipotle Sauce onto each plate. Place 1 lamb rack half atop sauce on each plate. Serve, passing re-maining sauce separately.