In a heavy-bottomed pan, heat the oil. Add all of the spices and cook while constantly stirring until fragrant. Add lamb and season with salt. Coat the lamb with the spices and oil. Add garlic and Roma tomatoes. Heat through.
Add the canned diced tomatoes with their juice. Cover and simmer on low until lamb is tender. Adjust seasoning with salt.
To make the rice: Heat the oil in a heavy-bottom saucepan. Add all the spices and cook while constantly stirring until fragrant. Add rice and stir for 1 minute. Add stock and bring to a simmer. Taste and adjust seasoning of liquid with sea salt. Reduce the heat to low; cover and cook for 12 minutes.
Remove from heat and keep covered for 5 minutes. Fluff with a fork prior to serving.
Serve the lamb over or with rice and garnish with fresh cilantro (coriander).