Add the roasted red pepper, Calabrian chile paste, salt and garlic to the bowl of a food processor. Pulse until the mixture is chunky and evenly chopped. Using your hands, break the feta up into large chunks and add it to the food processor. Pulse the mixture until the feta is incorporated into the pepper mixture. (The mixture should remain slightly chunky.) Refrigerate for at least 30 minutes for the flavors to come together. Serve with crackers, veggies, on sandwiches or burgers. Spicy feta dip will keep, refrigerated in an airtight container, up to 1 week.