Mix Wheat flour along with salt and add enough water to make a thin batter. Add chopped onion, chillies and curry leaves to the batter.
Heat tawa. Wipe it with oil. Mix the batter and add little water and make it slightly thinner than the idli batter. Pour one big ladle of batter in the tawa, starting from edge of the tawa and ending in the middle circlewise (like making rawa dosa). Pour a teaspoon of oil around the corners of the dosa. After it cooked oneside, flip it over and cook other side also. Remove it.
Note: You can also add little maida and rice flour to get more crispy dosa.