Heat 2 teaspoons coconut oil in a large nonstick skillet over medium-high heat until the oil shimmers.
Add 1 cup sliced red onion and sauté about 1 minute, stirring occasionally, until the onion begins to soften.
Stir in 1 large clove garlic, minced, and 1/2 teaspoon cumin seeds. Cook about 1 minute, stirring, until the garlic and cumin are fragrant.
Add 1/2 head green cabbage, thinly sliced, to the skillet. Sprinkle 3/4 teaspoon salt (plus more to taste), 1 teaspoon curry powder, 1/2 teaspoon garam masala, and 1/4 teaspoon turmeric over the cabbage. Add hot pepper flakes to taste, if using. Toss everything to coat evenly.
Continue to cook the cabbage, stirring or tossing occasionally, about 5 minutes more, until the cabbage is tender but still slightly crunchy.
Remove the pan from the heat, transfer the fried cabbage to a serving dish, garnish with chopped fresh cilantro leaves, and serve warm.