What planes have combat flaps and how do you control them?
"Combat flap" is not a special flap system in most cases. Rather, the official term was "combat setting" rather than "combat flap".
Flaps are primarily stabilizer devices, which provides more lift and lower stall speed at a price of increased drag, mainly used in dangerous low-speed situations such as in take-offs and landings.
However, it is quite evident that its effects can also be useful in certain combat situations - hence, some planes were designated a "combat setting" for flaps, which were sanctioned for use over much higher speed ranges than normal use.
However, structurally, there is nothing different from a normal flap from a "combat flap" - both are same part of a same flap system, merely differing in the angle they are deployed. The only exception which a flap system was mainly geared towards specific combat use, would be some of the Japanese Naval fighters using mercury-triggered automatic flap systems - which deployed or retracted automatically according to the AoA of the plane.
Therefore, basically, if you use flaps during combat, and it helps you achieve what you've desired, then effectively, you are using "combat flaps".