We returned from our first Oceania cruise. Loved the Red Ginger restaurant and the watermelon, duck salad.  Has anybody made it?  Can I use something else besides duck?  What's palm sugar and lemongrass stalk? Galangal? Thank you!       SWEET FISH SAUCE INGREDIENTS ¾ cup palm sugar, coarsely chopped ¼ cup water ½ large shallot, coarsely chopped 1 lemongrass stalk, bulb portion only, coarsely chopped 1 kaffir lime leaf ½-inch piece galangal,