Meats:

There are three major meats used in Chinese cooking:  chicken, beef, and
pork ("fowl" is a larger grouping than "chicken").  

Chicken can be cooked in many ways.  Usually the chicken breast is skinned,
and cleaned.  Then the chicken breast is cubed into small bite-sized chunks,
roughly 0.5"x0.5"x0.3" (depth varies).  The chicken is then marinated in
a wine (2 Tbsp), soy sauce (2 Tbsp), finely chopped ginger root, pinch of 
sugar, and finely chopped green onion (optional) mixture.  This is
allowed to marinate for about half an hour; the wine is added to absorb
strong/pungent meat flavors which might detract from the taste.  After
this half hour is up, 2 Tbsp of cornstarch are mixed in, until the
chicken cubes are completely covered in a sticky yet moist paste (there
should be no remaining liquid in the bowl, otherwise you have added too
little meat/cornstarch, or too much wine/soy sauce).  Note that although
I refer to the chicken as "cubes" they will not be; the chicken should
also have been defrosted before marinating, otherwise it will not absorb
the marinade.  Once this has been done, take the chicken and dump it
into a frypan/wok which has about 2-3 Tbsp of very hot oil, and stir-fry
the chicken at high heat until *just before* it is done.  The chicken
should still be pinkish and soft, otherwise it will be overcooked in the
final dish.  Note that the chicken should automatically separate from
each other as you stir-fry it (you can also add a dash of sesame oil for
a pleasing aroma).  Immediately remove the chicken at this point.  It
should be light to medium brownish, and still a touch squishy (raw).
Add to the frypan/wok the other ingredients/vegetables, and stir-fry
them until they are ready, _then_ add in the chicken again, and stir-fry
until the chicken cubes are just done.  This allows the vegetables to be
cooked to perfection, and the chicken to also be cooked to the perfect
degree of tenderness without the cook having to guess at doneness (if
you stir-fried all the ingredients together, you'd most likely overcook
the chicken; taking this route eliminates most of the guesswork).

It's possible to remove the skin and debone chicken thighs and legs and
then cube the dark chicken meat as well.  This is somewhat painstaking
and produces a slightly darker chicken in the final dish.  Chicken wings
should not be used, as they have little meat on them, and such that is
on them would probably be removed as strings, which are not
aesthetically pleasing.

On the other route, it is possible to take chicken breast (this is not
suggested for chicken thighs/legs), and very carefully slice them
horizontally, to produce large thin slices of chicken.  Marinate these
in the above sauce, and after the half-hour marinade period, dip each
cutlet into a bit of flour until it is completely coated.  Then place
each cutlet onto a frypan/skillet with a thin layer of hot oil for a few
minutes/side, pat dry on a towel, and serve.  Note that the chicken
cutlets should be cut very fine, on the order of an eighth of an inch
thick.  Other coatings than flour can be used, though it is the
marinade which provides the flavor.

Beef:

The Chinese rarely chunk beef, except for Americanized beef stews.  Beef
tends to be stringier and tougher than chicken, and so large pieces are
neither aesthetically pleasing nor so simple to eat (without getting
chunks of food stuck in your teeth).  For this reason, most Chinese beef
dishes tend to have thin strips of beef, either in the usual small
1/8-1/4 inch wide/deep by 1-2 inch long Yu Hsiang style, or in small 0.5"
x0.125"x (1-2)" strips, or in large thin cutlets.  It is *extremely*
important that beef is cut *against* the grain, such that there are no
long "strings".  Human teeth just aren't designed to work well on food
that tends to go with the grain (this holds for high-fiber vegetables,
such as many stem vegetables), as well.  Beef is marinated similarly to
chicken, although aniseed and/or five spice powder is also added (and
chili powders as well).  Beef tends not to be coated in flour mixtures,
save in such oddities as General Gau's chicken, although making cutlets
and coating them in flour and frying those is something parents
occasionlly do.

Pork:

My parents usually either cook pork similarly to beef, or they cook it
in stew form (i.e., crockpot).  Large amounts of soy sauce, sugar,
ginger root, wine, and varied spices get tossed in, and the pork is then
brought first to a boil and then down to a low simmer for several hours
until it is of desired tenderness (aniseed also).