1st. There will be a way. If you weren't aware, in order to use your special in Splatoon 2, you need to press down on the L Stick. And since the 3DS has an L Stick, just press on that to use the special.
2nd. Dodge-Rolling is a Splatoon-2-thing. There's a Splatoon 2 exclusive weapon class called 'Dualies' and they're basically shooters, but what makes them so special is that you can do something called Dodge-rolling. It's really cool, and it's why I main the weapon. Here's an image of the normal Dualies:
https://vignette.wikia.nocookie.net/splatoon/images/c/c3/SplatDualies.png/revision/latest?cb=20170605174511 And here's a video of someone dodge-rolling, it shows him dodge-rolling a lot, but the video is about a technique I didn't know existed until now:
https://www.youtube.com/watch?v=Ake_-RQx9Yk
Also, since the video link contains Splatoon 2 spoilers, I'm planning on doing a Sploon 2 Hero Mode let's play sometime soon on my channel.