Make 2 cups (dry) of steamed rice and set aside to cool.
Dice the onion, cabbage, zucchini, garlic and chili pepper and place in a mixing bowl.
Heat the oil in a large pan and add this vegetable mixture and gently sauté. Add oregano and pepper to taste.
When both mixtures have cooled mix together. Place the chaya leaves in a pile. in a steamer and steam for at least 5 minutes, until soft but not overcooked. The leaves should be flexible but not too soft.
Remove the leaves and allow them to cool on a smooth surface like a counter-cutting board or paper towel.
Place a large spoonful of the vegetable rice mixture on the edge of one leaf and roll up the leaf, closing the edges in as you roll.
Place the stuffed leaves in a baking pan greased with olive oil. Repeat until all the leaves and stuffing are used.
Cover the leaves with hot tomato sauce and sprinkle cheese and bake for 20 minutes at 350 degrees and the cheese melts.
