My Favorite KenKen App!
I've used several different kenken apps, and this is the quickest and easiest by far. It lets you select multiple squares, and when you enter your numbers, they show up (or are erased) in all selected squares. So when you have multiple squares that need 1-9 as notes, you select all of the squares, and just enter the numbers once. Likewise, to remove all 2's from a row, just select the squares, and type "2" once. A quick double tap moves you in and out of note mode. I'm not sure why it doesn't come up when I search for "KenKen" in the app store - it obviously should!