Combine the ground beef, onion, garlic, cumin, rice, salt, pepper and cayenne pepper in a large bowl and mix until well combined. 2.  Roll teaspoons of the mixture into oblong balls. 3.  Boil up a pot of water and dip the spinach leaves into it to soften them.  They should take about 1 minute to soften.  Plunge them immediately into cold water, then drain well. 4.  On a flat surface, position two or three spinach leaves so that they are overlapping each other. 5.  Place an oblong shaped ground beef ball on the leaves, pull the leaves up around the meat and roll up as you would a Swiss roll. 6.  Repeat until all the meat balls are used up. 7.  Heat the oil in a frying pan (12" saute pan) and pack the spinach rolls tightly into it. 8.  Combine the lemon juice, sugar and tomato juice in a bowl and mix well. 9.  Once the spinach rolls start to crackle a little in the oil, pour over the tomato sauce. 10.  Bring to the boil and then reduce the heat. 11.  Place a plate on top of the spinach rolls to prevent them floating and simmer for about 45 minutes. 12.  Don't let all the juice reduce - this spinach rolls should be nicely glazed, but not swimming in sauce. 13.  Serve on a bed of couscous or on their own as a side dish.