Since Thermal radiation is electromagnetic radiation, can it be disturbed by something similar to EMI i.e to not transmitting heat? I believe that the title should cover most of the question's substance. I am very uneducated in this subject, so I have no idea if this question is stupid or not. 
For instance, if a body radiates heat towards another (cooler) body - let's say in vacuum - is there a theoretical way of 'disturbing' that the heat reaches the other, cooler body according to e.g electromagnetic field theory? I.e. in a non-trivial way, make sure that the heat does not radiate or manipulating the heat radiation by 'electrical means'.
 A: Are you asking the question of perfect insulation around a body in a vacuum?
There is no such isolation. The only thing you can do is to use insulation materials with low thermal conductivity.
A good example of the use of such a material is the sheathing of satellites. The side facing away from the sun is prevented from falling quickly to zero Kelvin and the other side is prevented from rising to a hundred or more °C. But without continuous rotation of the satellite, the insulation becomes useless after a while.
You also ask about the redirection of EM radiation.
That's impossible in a vacuum. EM radiation consists of photons with their oscillating electric and magnetic field components. The frequencies are so high and the wavelengths so small that it is technically impossible to switch on and off external fields that would periodically influence the photon and push or pull it in any direction.
At the boundary of materials, the deflection of EM radiation is what happens at all times. But heat dissipation processes prevent your idea of using them for insulation.
