Drain and let cool for 10 to 15 minutes, then transfer to a blender with the tahini, lemon juice, coconut oil, garlic, ginger, cumin, coriander, turmeric, cardamom, onion powder, cayenne, salt, and several grinds of pepper. Blend until creamy. If the mixture is too thick, add water, 1 tablespoon at a time, to blend into a creamy consistency. Taste and adjust seasonings. Chill until ready to use.