Wash and dry the okra. Chop the okra into 1/2-3/4 inch pieces, discarding the stems. The easiest way to do this is to line a few of them up and cut them at the same time. Sprinkle up to 1/4 tsp salt on the okra and mix. Set aside.
Heat a skillet over medium-high heat and add the oil. Once hot, add half of the chopped okra. Stir-fry the okra, in two batches, for about 4 minutes or until the slime disappears and the okra starts to crisp. I like to sprinkle a bit more salt on the okra here. Use a slotted spoon to remove the okra from the pan and set it aside. Remove the pan from heat, and wipe clean to remove any excess seeds, if needed.
Heat another 2 tbsp of oil over high heat and add the onions. Sauté until the onions turn golden, about 10 minutes. If the onions start sticking to the bottom of the pan, deglaze with a tablespoon or 2 of water. And add the garlic and ginger, if using, and sauté for 30 seconds. Add the cubed tomatoes and cook until the tomatoes soften, about 3 minutes. Add the remaining 3/4 tsp salt, cumin seeds and spice powders (coriander, cumin, turmeric and red chili). Mix well and add the fried okra and green chili pepper. Sauté for a minute or two.
Lower the heat and allow the okra to simmer for a few minutes, stirring occasionally. Garnish with cilantro and a squeeze of lemon, if desired. This dry curry is typically served with roti, naan, or other bread but can also be eaten as a side with rice.