Preheat oven to 180 degrees C. Grease a baking tray and set aside.
Combine the cream cheese, sour cream, onion, garlic powder and sugar in a bowl and beat until soft and well mixed. Lightly stir in the flaked imitation crab meat.
Fill a bowl with lukewarm water. Remove a wonton wrapper from the stack and cover the stack with a damp paper towel to keep the wrappers from drying out. With your finger wet two adjoining edges of the wrapper with water and place about 2 teaspoons of filling in the center. Fold the wrapper into a triangle shape, pressing out all the air and sealing the edges well. Place the filled wonton on the prepared baking tray while you finish filling and folding the wontons.
Bake in the preheated oven for about 15 minutes, until the wonton edges turn brown and crisp. Serve immediately.