Cheesy Zucchini and Vegetable Balls with Creamy Herb Sauce

Ingredients
For the Zucchini Balls:

5 tablespoons oatmeal
1 zucchini, grated (1 cup or about 150g)
1 teaspoon salt
100g (3.6 oz) cheese, grated (cheddar or mozzarella)
1 carrot, grated (1/2 cup or about 50g)
2 eggs
Fresh parsley, chopped (2 tablespoons)
2 garlic cloves, minced
1 potato, grated (1 cup or about 120g)
Olive oil, for greasing
For the Sauce:

2 tablespoons Greek yogurt or sour cream
3 teaspoons mayonnaise
2 tablespoons ketchup
Fresh parsley, chopped (1 tablespoon)
Chives, chopped (1 tablespoon)