It;s a while since I've made them but they always worked really well without the buckwheat flour.
Otherwise I love a pile of smoked salmon and tiger prawns (cook your own if you want) topped with a little mayo (optional)and cayenne (paprika if you don't like the heat) and a good squirt of lime juice. Delicious on its own or with blinis, oatcakes, melba toast or nice bread.