Bring a large pot of water to a boil over medium heat. Add pasta and salt, to taste, and cook to al dente. Drain.
Add the red peppers to a small sheet pan and char to blacken evenly all over under the broiler. This also can be done over an open gas flame. Put them in a bowl and cover with plastic wrap to cool. Peel and seed the peppers, then chop and add them to a food processor. Add the stock and process to puree.
Heat about 1/4 cup extra-virgin olive oil in saute pan over medium heat, and add the garlic and green peppers. Cook for 3 to 4 minutes then stir in the puree. Add the drained orzo and season with salt and pepper, to taste. Stir in the pepperoncini and some juice and toss to coat. Transfer to a serving bowl and serve.