Combine onion, ginger, and garlic in a food processor; process until finely chopped. Heat oil in a large nonstick skillet over medium-high heat. Add onion mixture; sauté 5 minutes or until lightly browned. Add curry and coriander; cook 1 minute, stirring constantly. Add water, currants, sugar, salt, and chicken; bring to a boil. Cover, reduce heat, and simmer 20 minutes. Uncover; cook 20 minutes or until most of liquid evaporates. Remove from heat, and cool slightly. Stir in sour cream. Place the chicken mixture in food processor; pulse until finely chopped.
Place 1 phyllo sheet on a large cutting board or work surface (cover remaining dough to prevent drying); lightly coat with cooking spray. Sprinkle with 1 teaspoon coconut. Repeat layers 4 times. Cut crosswise into 4 strips. Spoon about 2 tablespoons chicken mixture onto one end of each strip. Fold 1 corner of edge over mixture, forming a triangle; continue folding back and forth into a triangle to end of strip. Repeat procedure with remaining phyllo, cooking spray, chicken mixture, and coconut.
Place triangles on a large baking sheet coated with cooking spray; coat with cooking spray. Bake at 400° for 18 minutes or until golden brown.