what do you mean no tenkan? do you mean some kind of direct iriminage? palm open straight to the uke's face?
something for you to think about. you can irimi moving forward. you can irimi moving backward. you can irimi moving in circle. there is no tenkan. "there is no spoon!".
hint: think of that in term of intent and energy
also, did i mention that i also like sokumen irimi nage? just going to rotate my body and put my fist where his head is going to be (got that one for Chuck Clark sensei) and let uke makes the choice of impaling on my fist or take ukemi.