Cook the pasta according to the packet instructions, drain and set aside.
Heat the oil in a large pan. Add the onions, beans and sweet corn and cook for 3-4 minutes.
Add the beef strips and cook for 2-3 minutes until brown then remove from the heat.
In a small bowl mix the greek yogurt with the mustard and lemon zest. Add to the pan with the beef and stir through the hot pasta. Season and add the chives.
Spoon into pasta bowls and serve immediately with crusty bread.