1. Combine sliced strawberries and 3 tablespoons sugar in a small bowl; stir well. Let stand 15 minutes.
2. While sliced strawberries stand, weigh or lightly spoon flours and potato starch into dry measuring cups; level with a knife. Combine flours, potato starch, remaining 1 tablespoon sugar, baking powder, and salt in a medium bowl; stir with a whisk. Combine coconut milk, vanilla, and eggs; stir with a whisk. Add to flour mixture, stirring with a whisk until smooth. Fold in diced strawberries.
3. Heat a nonstick griddle or large nonstick skillet over medium heat. Pour 2 1/2 tablespoons batter per pancake onto pan; cook 1 to 2 minutes or until tops are covered with bubbles and edges look cooked. Carefully turn pancakes over; cook 1 to 2 minutes or until bottoms are lightly browned. Spoon sliced strawberry mixture over pancakes, and sprinkle with toasted flaked coconut.