Understanding circuit diagram on datasheet and resistor value
To start with your last question: yes, it's a microcontroller (not a microchip, that's a confusing word since it's the name of a manufacturer of a.o. microcontrollers).  

Unfortunately the supply current is not for you to choose. At 3.3 V it will be typically 0.35 mA, but it can be anything between 0.27 mA and 0.45 mA. And the 10 k&Omega; you calculated is the equivalent resistor of the receiver's power consumption.

The resistor in the schematic forms a low-pass filter with the capacitor, letting DC and low frequencies pass and filter out the higher frequency noise. That resistor will cause a small voltage drop from the power supply; the higher the current, the higher the voltage drop, due to Ohm's Law. So worst case the current will be 0.45 mA, and then the 1k&Omega; resistor will cause a 450 mV drop. If you supply 3.3 V then the receiver will have 2.85 V left. This is enough to operate, but you have to take into account that it will only output 2.85 V as a high level, and you have to check that this is enough for the microcontroller.  

You're right about the working of a decoupling capacitor, and that's part of its job. Like I said the capacitor is also part of a filter. If you choose 1 k&Omega; for the resistor, and 100 nF for the capacitor it will have a cutoff frequency of 1600 Hz.