dude, the chapter they kissed in was just some funny spin-off thing about momiji tricking ichiko into marrying her. It had nothing to do with the story, so no it wasn't "canon" but jeez can't you let me dream? You can look at ayano-chan's link if you really want to see it.
People wanted them together because nobody gave a damn about Keita and him and Ichiko had no chemistry at all. People would rather watch Ichiko and Momiji bicker but at the end of the manga they had a very tearful moment with each other and that's why people ship them. .