1. In a medium bowl, whisk the yogurt, cilantro, puree, salt and pepper. Reserve 1/2 cup of the marinade.
2. Thread the salmon, scallops and shrimp onto 4 metal or wooden skewers, using 3 pieces of each per skewer in a repeating pattern. Skewer the shrimp twice, so it passes through the body close to both of the ends. Pour the marinade over the seafood, turning to coat evenly.
3. Broil or grill the brochettes for about 10 minutes. At the halfway mark, turn, and baste with the reserved marinade.