In a large bowl, cover lima beans with water, cover with a towel and soak overnight.
In a large pot, add oxtails, onions, scallions, garlic, thyme, red pepper, paprika, bay leaf, hot sauce, and gravy master and marinate at least 4 hours or overnight in the refrigerator, stirring occasionally.
Add enough water to just cover the oxtails and bring the mixture to a boil. Lower to a simmer, cover and cook 2 hours. Every 30 minutes for 2 hours add 2 cups of water or broth, alternating, as necessary, to keep oxtails covered with liquid.
At 2 hours, add the beans, tomato paste, and 2 more cups of beef broth and water, if needed. Bring to a boil then simmer uncovered 2 hours, skimming fat off top and stirring occasionally. In the last 1/2 hour of cook time, season with 2 tablespoons salt. Serve with rice.
Rinse rice 3 times to remove starch. Put rice in a medium saucepan. Fill saucepan with enough water to cover the rice by 1/2-inch or measure by placing your thumb tip on the rice and filling the pot with water until the water reaches the middle of your thumbnail. Bring rice to a simmer, cover and cook until tender and liquid is evaporated, about 15 minutes. Remove from heat and let rice stand another 5 minutes, covered.