Shrimp goes quite nicely with cucumber. I have in my collection of LC recipes (collected from around the internet) several where the “cracker” is a slightly thicker slice of cucumber, with various toppings. Or a piece 1 to 2 inches long, slightly hollowed out to form a cup. Another cup like thing would be a piece of bell pepper. Your salmon, cream cheese, and horseradish reminds me of something that usually goes over well with guests. thinly sliced smoked salmon (lox) spread with cream cheese mixed with wasabi or horseradish, and then rolled up like a jelly roll. Chilled thoroughly, in the freezer for a bit to firm it up, then rolled in sesame seeds (or chopped parsley or chives), and sliced. Its a little fiddly, but laying the salmon out on plastic wrap makes it much easier. DH calls it Swedish Sushi :-)