Generally if we are making any veggies, it is usual to sprinkle some water to cook them. But for lady's finger you should not. If you want to get a crispy vendakkai roast there are two things to follow. First do not add water and then add salt only at the end. Please refer above for preventing slime. Also the okra will reduce in quantity when you fry it. So keep that in mind while preparation.
Okra Fry | Vendakkai roast https://www.themagicsaucepan.com/main-course/veggies-poriyal/okra-fry-vendakkai-roast