Sprinkle duck legs with salt and pepper. In large, deep skillet over medium-high heat, heat oil and swirl to coat bottom of pan. In batches, add duck legs, skin side down, and cook for 4 to 5 minutes a side, turning once. (A spatter screen will help the fat from spitting out.) As they brown, remove the legs to large shallow roasting pan or casserole dish. Pour off all but 1 tbsp (15 mL) fat and reserve for another use. (It freezes well.)

Reduce heat to medium and add onion to skillet. Cook, stirring often for 5 minutes. Stir in garlic and cook 1 to 2 minutes or until fragrant. In small bowl, stir together paprika, red pepper flakes, sugar, cumin, oregano, cinnamon and cloves. Stir into onion mixture until well blended. 

Stir in broth, vinegar, soy sauce and bay leaf. Bring to boil, scrapping up any brown bits from the bottom. Pour over duck legs, cover pan with parchment, then foil and bake in 350°F (180°C) oven until duck is tender when tested with fork, about 2 hours. Discard bay leaf. Serve sauce over duck and any extra in pitcher to pass at the table.