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 for two hours. Every 30 minutes for two hours add 500ml of water or broth, alternating, as necessary, to keep oxtails covered with liquid.
At 2 hours, add the beans, tomato paste, and two more cups of beef stock and water, if needed. Bring to a boil then simmer uncovered for two hours, skimming fat off top and stirring occasionally. In the last half hour of cooking time, season with two tablespoons of salt.
Serve with rice.
For the rice: Rinse rice three times to remove starch. Put rice in a medium saucepan. Fill saucepan with enough water to cover the rice by 1.5cm 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 five minutes, covered.