Stir-fried Okra with tomatoes, onions, and Indian spices

Combine the oil and cumin seeds ina large wok or frying pan over medium-high heat.  Cook, stirring, until fragrant, 1-2 minutes. Add the ginger and cook, stirring, 30 seconds.  Add the onion, cook until translucent, about 3 minutes. Add the coriander, ground cumin, turmeric, and cayenne.  Turn heat down to medium and cook 30 seconds.Add the okra and stir to coat with spices.  Then cover and cook until the okra browns lightly, about 5 minutes.  Stir once or twice during this time and check the cooking.  If the spices begin to burn, turn the heat down; if the okra doesn't brown, turn the heat up.Add salt and tomatoes and stir well.  Turn the heat down to low, cover and cook 5 minutes.Uncover, turn the heat up to high, and cook, stirring now and then until the liquid is gone and the okra is tender, about 5 more minutes.  Stir in lemon juice and cilantro and serve hot.