Boil the sweet potatoes in water for 8 minutes, or until tender. Mash and combine with the tofu, cabbage, garlic, 3 tablespoonsful of the sesame oil, and the soy sauce.
Assemble by placing 1 tablespoonful of the mixture onto each dumpling wrap and folding over. Use a tiny bit of water to seal the edges. If desired, fold in half and bring each end together, creating a rose-shaped dumpling.
Fry in the remaining sesame oil. When browned, add the water to the pan, cover, and steam for 2 minutes to cook thoroughly.