In a bowl, mix together the butter, lime juice, garlic, and spices, until well-combined. Add the shrimp and stir to evenly coat. Let marinade for 10-15 minutes.
Meanwhile, heat the grill or grill-pan over medium-high heat. Add the pineapple slices to the grill and cook until golden, about 3-4 minutes per side. Remove from the grill and set aside. Add the shrimp to the grill pan and cook until opaque, about 2-3 minutes per side, depending on size.
Cut the grilled pineapple rings into chunks. Divide the shrimp and pineapple evenly among the tortillas, top with the jalapeño, cabbage, cheese and cilantro.