Wireless signal reflection/absorption on different materials
What causes RF waves to reflect or absorb?
  The material, more specifically if its conductive or not. 


If the material is perfectly conductive you get a reflection which follows snells law. If the material is not conductive you get some of the wave that does not get reflected and enters the material, at which point it probably get attenuated. 

Source: Antennas

Take for example a wall, the boundary between the air and the wall causes a reflection, and some of the wave enters the material of the wall. The wall has an impedance, which means some of the wave will also get absorbed (ohmic losses, not shown in the equations below). And then more relfection on the way out. 




  Does the reflective/absorptive property of RF waves act similarly to
  light properties?
  Yes very similar, infact the optics equations can be derived from electromagnetic equations. The differences are the frequencies and the materials.


Usually we use seperate equations in optics and in electromagnetics, because of the difficulty of working with these equations. Usually ohmic losses in RF are from 

As your questions stand they are probably too broad for the scope of this site, however, I took a crack at answering them anyway. If your really interested in this, then pick up any Electromagnetics Theory book.