Combine samp and cowpeas in a large glass bowl. Add cold water sufficient to cover. Cover, and let stand overnight. Drain and rinse before cooking. Place the soaked samp and cowpeas in a large pot and cover the mixture with cold water. Bring to a boil. Let boil for 10 minutes. Reduce heat. Simmer on low heat for 1-2 hours, until all is tender and the water is mostly absorbed. Add additional water during cooking if needed. Season with salt. Serve hot.