1) Make the marinade: In a small bowl, combine 1/4 cup lime juice, 1/2 cup olive oil, 2 tbsp soy sauce, 4 cloves garlic minced, 1 tbsp brown sugar, 1 c. cilantro, and 1 tsp salt. Place 4 (4 oz) salmon filets in a glass dish and cover with marinade. Allow to marinate for up to 1 hour in the fridge. Reserve marinade for grilling. 2) Grill the Salmon: Slice 2 lg pineapples into eight planks. Place the marinated salmon on the flank of pineapple and top with a few sprigs of cilantro. Top with another flank of pineapple and wrap with kitchen twine. Place salmon on warm grill and cook for 5 minutes. Flip over and remove the twine. Baste with remaining marinade and cook for another 5 minutes until salmon is tender and pineapple is slightly charred. Remove from grill and allow to rest for 5 minutes before serving.