Sort through peas to remove any pebbles or other foreign matter. Rinse peas. In a large saucepan combine peas and the 5 cups of the water. Bring to boiling; reduce heat. Cook, uncovered, for 10 minutes. Remove from heat. Drain and rinse peas.
In a 4- or 4-1/2-quart slow cooker combine peas, the remaining 3 cups water, the quartered jalapeno peppers, sage, and salt. Top with meat.
Cover and cook on low-heat setting for 8 to 10 hours or on high-heat setting for 4 to 5 hours.
If using low-heat setting, turn to high-heat setting. Stir squash into mixture in cooker. Cover and cook for 30 minutes more. Sprinkle each serving with red onion and cilantro. If desired, top with Lime Sour Cream and chopped jalapeno pepper. Makes 6 servings.
Lime Sour Cream
In a small bowl combine sour cream, lime peel, and lime juice. Cover and chill before serving.