The Rema (Darkei Moshe) writes that when we tell the story of yetzias Mitzrayim at the Seder, it is like a tefillah, because we are praising Hashem. He says that this is the reason we wash our hands for Urchatz, because “just like we wash our hands before we daven” we also wash our hands before we say Hashem’s praises, which is a form of tefillah.