Line a small baking pan with wax paper.
Place salmon in a medium bowl. Flake chunks into very small bits. Add chopped chicken and mashed sweet potato and mix well. Stir in rice flour.
Place a lightly greased 3-inch round cutter on the baking pan and spoon ⅓ cup salmon mixture into the ring. Using fingers, firmly pat mixture out into an even layer. Carefully remove ring and repeat with remaining salmon mixture. Place pan in freezer for 15 minutes to firm up the patties.
To assemble cake, place one patty on a small plate. Spread with the peanut butter and top with another patty. Decorate top of cake with the yogurt, letting it run down the sides of the cake to create the drip cake effect.
