What is that box next to the plumbing, what is the purpose of the step under the sink.I have no idea how you would have a shelf under the sink unless it was custom made.Maybe you could actually look at a custom made piece with the sink in it.

Looks like a tankless water water heater. Also looks like plumbing was but above ground for what ever reason...either find out why and correct it if possible or find a vanity and custom cut the back to slide against the wall.

It's a heater under the sink. I have no idea why the thing is where. And why the step is there. . . strange design.