Well I have never bought belly with skin on but others I know have and some trim before smoking and others will trim after smoking as they say this makes it a lot easier to trim. When ever I trim any kind of meat I always use my filet knife and go slowly. You do not want to trim all fat off as that's what makes bacon so good
Just take your time and i'm sure you will do fine on the trimming of it.
On curing this is the way I do it.
Rub cure mixture on belly making sure to cover the entire surface. Place skin side down in a 2 gallon sealable bag, and expel all air, and fold the empty end of the bag under so that the belly is in close contact with the bag. During the curing time the belly will release liquid, and it is important that this liquid stay in contact with the meat. Refrigerate at 34 - 40°F (the closer to 40°F the better) for 5 - 7 days, until belly is firm to the touch with no soft spots. During the curing time, turn the bag over once a day or once every other day to redistribute the cure.
When belly is fully cured, rinse it thoroughly, and pat it dry. Place it on an inverted rack set over a baking sheet, and air dry uncovered in the refrigerator overnight (12 - 24 hours).
If you don`t have the refrigerator space to air dry the bacon you can do this step in the smoker. Preheat the smoker to 100 - 120°F with vent wide open, and place your room temperature bacon in the smoker. To get these low temperatures you will need to use a "cold smoke setup". Do not apply smoke at this time. You just want to dry the bellies until they are tacky when touched. Depending on the size of your load, this generally takes about 2 hours, but to be on the safe side check the bellies after one hour.
Once bacon has been "air dried" place into a 120 - 140° preheated smoker with vent half open.
The amount of smoke is up to you. I generally will only apply 2 hours, using maple.
After you have applied your smoke, increase the heat to 160°F, and smoke/cook the bacon until an internal temperature of 150°F is reached. Or you can finish it to an IT of 132*F if you plan on finishing it off in the frying pan, this is more like store bought bacon.
After the desired internal temperature has been reached, remove from smoker and allow to cool slightly. When cool enough to handle, but still warm pull the skin off (you may need a sharp knife to help) making sure you leave as much fat on the bacon as possible.
