Salmon Skewers with Spicy Pineapple Sauce

Name: Salmon Skewers with Spicy Pineapple Sauce
Ingredients: 1 lemongrass stalk, lightly bruised; One 4-in. piece of kelp; One 13.5-oz. can unsweetened coconut cream; 1 cup bonito flakes; One 3-lb. pineapple, peeled, cored, and sliced 2-in. thick; 2 Tbsp. vegetable oil, divided; 1 Tbsp. miso; 1 Tbsp. tomato paste; 2 Tbsp. fresh lime juice; 1 Tbsp. sambal oelek or other chile paste; 1 tsp. finely grated galangal; 1 tsp. finely grated ginger; 1 tsp. smoked paprika; Fish sauce; 3 lb. Norwegian salmon fillet, cut into 1-in. cubes; Kosher salt; Thinly sliced cabbage, warm corn tortillas, cilantro leaves, and toasted sesame seeds, for serving (optional)