I have a Pinterest clone website (general / multiniche adult), and I have not been getting any results on that. I tried adding straight keywords to pin descriptions, and also longer text, but it does not seem to work. Organic traffic in Google Analytics equals 0 (5 a day at the most, only about 200 unique visitors a day to the site for now).
Try 'optimizing' the page. I.e. if you have a board about wedding details utilize the description area and write for that keyword. I do see some boards come up on organic results, but I have no idea how or why. I just did a quick search now though and it looks like there are no longer any pinterest boards on the search result where formerly I saw at least 3 different listing from the site. My guess is they were showing up due to algorithm change and now they are not showing up at least within the 1-4 page results.
No, the urls look something like this: domain.com/pin/3d017ba05931017b15345e3ae2c73cd0 I don't think there is a way to change that.