Place eggs in a saucepan; cover with water. Bring to a boil, remove from heat, and let eggs stand in hot water for 15 minutes. Remove eggs from hot water, cool under cold running water, and peel.

Cut eggs in half lengthwise; place yolks in a small bowl. Mash egg yolks with a fork; stir in tuna, pickle relish, mustard, sugar, and onion powder. Stir mayonnaise into tuna mixture until mixture is creamy but remains firm; season with salt and pepper.

Place egg whites cut-side-up on a serving platter. Spoon tuna mixture into egg white halves; sprinkle with paprika.