An AC dimmer won’t work with 12V power sources.
You need two controllers like this one to dim the 12V LED strips, one for the cabinet and one for the island:
http://www.amazon.com/Fibaro-857934005157-RFBW-Controller-Black/dp/B00P1N68FW
Just use one of the four channels. Then get a smart dimmer switch but don’t connect the load and use the “Big Dimmer” app to dim them virtually.