Check peas for debris, and rinse thoroughly. In a large pot, sauté aromatic vegetables (onions, garlic, celery, carrot, etc.) in olive oil. Add peas and enough water to cover by about 2 inches. Bring to a full boil for 10 to 15 minutes. Reduce heat to a gentle simmer, using a lid to help regulate the heat, and gently cook until done, 30 to 90 minutes. Salt when the peas start to soften. A pre-soak of 2 to 4 hours will lessen the cooking time.