To hard-boil the eggs, place in a small pot and cover with cold water. The water should be at least one inch over the eggs. Bring just to a boil over medium heat. Cover and remove from the heat. Let sit for 10 minutes. Place in a strainer under cold running tap water to cool. Peel and cut in half.
Scoop out yolks and add them with yogurt, sriracha, mustard, salt, and paprika to a blender or food processor and puree. Carefully scoop back into egg whites or pipe into the whites.
Garnish each egg with a slice of cucumber, if desired.