Is it permissible to supplicate with evil against one who unjustly harms animals, such as one who flays them alive or intentionally slaughters them with a dull instrument, and that after prayer and at any time?

It is forbidden to torture animals or to mutilate them. The Prophet, peace and blessings be upon him, cursed those who do so. It is also forbidden to slaughter with a dull instrument unless necessity dictates it. However, the slaughtered animal is halal (definition) if slaughtered with it, even if the act itself is forbidden. It is disliked to slaughter with a dull instrument, to sharpen it while the animal watches, to orient the animal away from the Qibla (definition), to break its neck, or to skin it before it has cooled down. It is not prescribed to supplicate against a Muslim merely because they have sinned by torturing an animal.