Heat canola oil in a skillet over medium heat.

Add black mustard seeds and onions to the skillet.

Cook until the onions are translucent and the mustard seeds start to pop.

Add sliced green chilies, green beans, salt, and pepper to the skillet.

Cover the skillet and cook over medium heat, stirring occasionally.

If needed, add a little water to prevent sticking.

Continue cooking until the green beans are tender-crisp and the water has evaporated.

Ensure the dish is dry and not liquidy.