Soak the eggplant strips in water and set aside. Heat the olive oil in a large skillet over medium-high heat. Add the mustard seed and let cook 2 minutes. Add the cumin seeds and curry leaves, if using, and sauté 1 minute. Add the onion and sauté while stirring for a minute. Add the turmeric, sauté, stirring frequently, about 3 minutes, until the onion is translucent. Cover and cook, stirring regularly, until the onion is golden and caramelized, 7-8 minutes.
Drain the eggplant strips and add to the skillet. Mix thoroughly until eggplant strips are coated with the spice and onion mixture. Cover and cook for 5 minutes, stirring occasionally to prevent sticking. Add 1 teaspoon sea salt, stir well, and continue cooking, covered, for an additional 4-5 minutes. Add the chili pepper and the garlic-ginger paste, if using, and stir well. Continue cooking for 1 minute. Add the garam masala and continue cooking until eggplant is nice and fried, about 2-3 minutes more. Remove to a serving bowl and garnish with fresh cilantro. Bon appétit!