Make the blini: Place a wire rack over a baking sheet. Set aside.
In a large mixing bowl, gently whisk together the egg yolks, half and half, and 3 tablespoons of the melted butter.
In a small bowl, whisk together the almond flour, coconut flour, baking powder, and 3/4 teaspoon salt. Fold into the egg yolk mixture.
In the clean, dry bowl of a stand mixer fitted with the whisk attachment, whip the egg whites until light, white, and fluffy, holding firm peaks, 2 to 3 minutes.
Gently fold the egg whites into the flour-egg yolk batter until combined. Do not overmix (you’ll get flat blini).
Heat a nonstick skillet over medium heat. Add 1 tablespoon of the melted butter. Spoon heaping teaspoons of batter into the pan about 1 inch apart, use a small spatula or back of a spoon dipped in melted butter to gently but quickly smooth and form each into a roughly 2 to 2 ½-inch disc and cook until golden, 1 to 2 minutes. Gently flip and repeat on the other side. Transfer the blini to the prepared wire rack. Repeat with the remaining butter and batter to make approximately 24 blini.
To serve: Arrange the blini on a platter. Top each with some smoked salmon, 1 ½ teaspoons sour cream, and a sprinkle of chives.