In a large bowl mix together the buckwheat flour, baking powder, a pinch of salt and freshly ground black pepper and milk until reaching a smooth lump-free batter.
In a separate bowl, whisk the egg whites until soft peaks form, then gradually fold the whisked egg whites into the batter mixture, until fully incorporated.
Grease lightly with olive oil a large frying pan and heat over medium high heat, then spoon a tablespoon of the batter into the pan to make a small bite-sized pancakes, about 3 cm large.
Cook the pancakes for one minute, then flip them on the other side and cook for a further minute, or until golden on both sides. Remove the pancakes from the pan and keep them warm.
In a small bowl smash the avocado with a fork until creamy, then add in the yogurt and lime juice, season with sea salt and black pepper to taste and mix until all the ingredients are combined.
Place one teaspoon of the avocado cream over the gluten-free blini, then top them with smoked salmon, sprinkle the lime zest on top and serve.