You will notice that no salt is called for in this dish. The sea asparagus has a natural briny saltiness to it, and the cheese will also add some, so you don't need to add any of your own. Instead of sea asparagus (in case you can't find any) feel free to use steamed asparagus, steamed broccoli or chopped zucchini. If using asparagus or broccoli, steam to just tender, no more.
If using zucchini, you can add raw, just add it so that it can warm through a 2 minutes or so. In which case, you may want to add it before the rice is thoroughly cooked, as you will still need to add broth. If you add the zucchini too late, in order to cook it through, you will dry out the rice. So be prepared with stock.
This serves 2-3 people as a main, or 4 comfortably as a side dish