1. In a pot over high heat, stir together pomegranate juice, sugar and lemon juice until sugar dissolves. Boil until liquid thickens and is reduced to 1 cup, about 45 min.
2. Meanwhile, toss shrimp with cumin, coriander, cinnamon, salt and olive oil and stir to coat.
3. In a bowl, toss arugula with extra lemon juice and olive oil if desired. Place on a platter.
4. Heat a grill pan over medium heat. Add shrimp and cook 2 min per side until pink and opaque; place on top of arugula. Pour sauce in a small dish for dipping. Makes 10 servings, or 4 servings for main course.