Gently mix together the ground pork, shrimp, jicama, salt, pepper, fish sauce, shallot, garlic and bread crumbs until just combined. Be careful not to overmix this as it will result in a tougher meatball texture.
Shape the mixture into 16 golf ball sized meatballs with lightly oiled hands. You can also use a tablespoon or a small scoop. Feel free to make the meatballs larger or smaller depending on what you want to eat them with.
Arrange the meatballs in a heat-safe plate or tray and steam them until just cooked. This will take about 15-20 minutes for golf-ball sized meatballs. They will release some liquid while they steam. Keep this to make the sauce.
While the xíu mại are steaming, make the sauce. Bring a small pot of water to boil and carefully place the tomatoes in for about 30 seconds, or until the skin easily peels back. Peel the skin back and blend them until smooth.
In a heavy-bottomed with a little bit of oil, heat the tomato puree over medium heat until a rich red color develops and the tomato puree has thickened. If you drag a spatula across the bottom of the pot, you should be able to see the bottom for a second before the sauce pools back down.
When you're happy with the color of the tomatoes, add 1 cup of chicken broth or water.
Once the xíu mại are ready, take them out of the steamer and carefully add them to the tomato sauce, along with any liquid that they may have released.
Season with more salt and pepper to taste.