The Kv of a motor is how many rpm’s per volt. The higher the Kv the faster it will spin, likewise the higher the voltage the faster it will spin.
When we talk about Kv and prop size, think transmission. High Kv motors (2200) need smaller props and are similar to high gear in a transmission, little lugging power but goes fast. A lower Kv motor (1200) will swing a larger prop and is similar to low gear in a transmission, lots of lugging power but limited speed. A tractor and a race car may both have the same horsepower, one is built for speed and the other for pulling large loads. With electric motors, the power is measured in watts, high Kv motors are for speed, low Kv motors are for lifting heavy loads.
Regarding ESC’s the amp rating is a do not exceed number. If the motor draws more amps than the esc is rated for, the esc will burn out. Batteries have a similar limit, if you exceed the amp rating, you will damage the battery. With batteries, the amp limit is calculated, the formula is MAH/1000 x C. Example: a 2000 mah 20C battery can safely supply 40 amps (2000/1000 x 20=40).
When selecting components, start with the motor, how many amps will it draw. Then select an ESC that can supply a bit more, the Rx and servos will also draw a few amps and a bit of headroom never hurts. Then select a battery that can supply the amps required.