Two things worked for us.
1. We used a foam bath/sun visor in the tub. When I'd rinse my child's hair, the water would run off the visor instead of into their eyes. They hated water on their face. Even using a washcloth didn't work. If the cloth got wet (which it does) watch out ! So visor it was. Go to Babies R Us for these. I pasted a link to what they look like.
http://www.toysrus.com/product/index.jsp?productId=2792398
2. If you have a highchair that can be adjusted high enough and tipped back so you can rest her hair/head over the edge of the sink salon style, do that. If possible, maybe put a cushion under her bottom to give her a little height. Be sure to buckle her in for safety.
I didn't have a high chair like with my first so couldn't do it. I could with the next.
What I did with the first was this; You could try washing her hair with her laying on her back ontop ot the kitchen counter with her hair and head slightly over the edge of the sink. Be really careful. If she freaks out you wouldn't want her to fall. Be sure to stand in such a way to block her if she panics or rolls. I used to put a towel folded in half length wise on the counter to catch water and for comfort, and a second towel rolled like a neck roll. Just pour the water or use the sprayer in such a way that water doesn't roll in her face.