Sure, as long as you don't mind a lack of specifics.
First, chop up a large sweet onion or two, a bell pepper or two, and a bunch of garlic. Add a little olive oil to a large pot and saute the above until the onion starts to carmalize.
If you are using fresh green chilies, chop them up and throw them in at the start. If you are using canned green chiles, add them when you add the tomatoes.
Once the onions and peppers are ready, add your tomatoes. If you are using fresh tomatoes, you'll want to boil a pot of water, add the tomatoes, and leave them in there for a couple minutes until the skins start to split. Once the skins split, put them in a sink of ice water to cool so you can handle them. Remove the skins once they cool down. Cut out the core and any bad spots before adding to the onions. If I have any slicing tomatoes that I will be using, after I remove the skins I squeeze out as much water and seeds as I can before adding them to the main pot. That step isn't necessary with paste tomatoes. FYI, it takes a lot of tomatoes to make a batch, especially if you are using slicing tomatoes. In the picture above, I believe that is a 9 quart pot and I used about 4-5, one gallon ziplock bags that were stuffed as full I as could get them without mashing the tomatoes. Two-thirds to three-quarters were slicers.
Also, if you grow your own tomatoes and don't have enough to make a batch of salsa, you can just freeze them until you get enough. If you freeze them, you don't need to boil them to get the skins off. Just make sure you cut out the core and any bad spots before freezing.
Once the tomatoes are in, add hot peppers to taste. I use jalapeños because they are about the right amount of hot for me. A quarter cup or so finely chopped if fresh, a little more if canned.
Now is also the time to add the seasoning. Add cumin, red pepper flakes, and cayenne powder to taste. Don't over do it with the seasoning and hot peppers. You will be boiling a lot of the water out so the flavors will become much more concentrated than they are at this point. You can adjust the seasoning later if need be. Also add a little lemon and lime juice. A half of each squeezed into about a gallon batch is about right.
Next, use a hand blender to chop up the tomatoes and mix everything together but don't over do it at this point.
Once everything is mixed, bring the pot to a low boil and allow it to simmer uncovered, stirring occassionally. Now is the time to get the moisture out and thicken everything up. How long to let it simmer will depend on how much water it started off with. That will largely depend on the type of tomatoes used. I usually let it cook for a couple hours. Keep in mind that while it is hot, it won't be as thick as it will once it cools.
Once it has simmered to the desired thickness, destem one bunch of cilantro and toss it in. Only use the leaves, not the stems! At this point, give it a final mixing with the hand blender to make sure everything is nice and finely chopped but not so much that it is liquified. This is more of a restaurant style salsa, not a chunky salsa like pace.
Allow it to simmer for about 10 minutes after adding the cilantro and then remove from the heat. You can taste test it at this point but it won't taste quite the same as it does once it cools. I usually let it cool to near room temperature and then taste it to see if anything needs to be adjusted. You can always put a small cup of the salsa in the freezer for a bit to cool it down faster if you're impatient.