hi, first depends where you are staying ,stay close to nathan rd there are plenty of indian restuauants ,pls check out mccafe and local shps selling hotdogs and fishfry .near mongkok mtr station plenty of joints .my suggestion stay in kowloon near some mtr .i stayed at cosmo mongkok .good place ,just google it
If u are looking for a pure veg, I would definitely suggest visiting BRANTO Indian Restaurant in Kowloon side of Hong Kong. Run by Indians and very reasonabely priced. Directions are:
On main Nathan road, take the lane opposite popular Chunking Mansion, go straight, cross Pizza Hut on your left and just at next intersection, turn right. It is there in the beginning itself in the 3rd or 4th building on left. Its quite popular there, so anyone can guide you.
You can also visit the Pizza Hut coz they offer good Veg Pizzas.