1.Place stock and the water in medium saucepan; bring to a boil. Reduce heat; simmer, covered.
2.Meanwhile, heat olive oil in medium saucepan; cook onion and garlic, stirring, until onion softens. Add rice; stir to coat in onion mixture. Stir in ½ cup of the simmering stock mixture; cook, stirring, over low heat until liquid is absorbed. Continue adding stock mixture, in ½-cup batches, stirring, until liquid is absorbed after each addition. Total cooking time should be about 35 minutes or until rice is just tender. Stir in herbs and tomato, cover; cool 30 minutes.
3.Roll heaped teaspoons of the risotto mixture into balls; press a piece of cheese into centre of each ball, roll to enclose. Coat risotto balls in breadcrumbs.
4.Heat oil in wok; deep-fry risotto balls, in batches, until browned lightly and heated through.