Prepare the Bitter Melon: Wash the bitter melons thoroughly. Trim off the ends. Slice them in half lengthwise and use a spoon to scrape out the seeds and pith. Cut the bitter melon halves into thin, half-moon slices (about 1/8-inch thick).

Salt and Rinse: Place the sliced bitter melon in a bowl and toss with 1 tablespoon of salt. Let it sit for at least 20-30 minutes. This process draws out excess moisture and some of the bitterness. After resting, rinse the bitter melon slices thoroughly under cold running water to remove the salt. Squeeze out as much excess water as possible.

Sauté Aromatics: Heat the cooking oil in a large skillet or wok over medium-high heat. Add the thinly sliced onion and sauté until softened and translucent, about 3-4 minutes. Add the minced garlic and grated ginger, and cook for another minute until fragrant.

Cook the Bitter Melon: Add the rinsed and squeezed bitter melon slices to the skillet. Stir-fry for 5-7 minutes, until the melon begins to soften and turn slightly tender. You want it to retain a slight crispness.

Add Spices and Liquids: Stir in the turmeric powder, ground cumin, and red pepper flakes (if using). Cook for 30 seconds until fragrant. Pour in the water or vegetable broth, soy sauce (or tamari), and rice vinegar. Stir well to combine.

Simmer and Finish: Bring the mixture to a gentle simmer. Cover the skillet and let it cook for another 3-5 minutes, or until the bitter melon is tender to your liking. Uncover and cook for an additional minute or two if there is excess liquid, allowing it to reduce slightly.

Serve: Taste and adjust seasoning if necessary. Garnish generously with fresh chopped cilantro. Serve hot as a flavorful side dish or a light main course.