In a medium bowl, combine panko bread crumbs and milk and allow bread crumbs to soak up milk.
While the bread crumbs are soaking, heat 1 tablespoon olive oil in large pan on medium high. Add chopped onions and sauté until translucent, about 5 minutes. Add garlic and oregano and sauté for another minute. Remove from heat.
Add sautéed onion/garlic/oregano mixture from the step above to the bowl with the soaked bread crumbs. Add salt and pepper and 1 egg. Combine using a wooden spoon until the entire egg is mixed in. Next add ground beef and pork and mix everything well.
Using a tablespoon for measuring and your hands for rolling, start making those meatballs. I just rolled them between my palms and got 18 average size meatballs. You should get anywhere between 12 small to 20 large meatballs.
On medium high heat, brown meat balls on all sides, carefully turning so they don't break apart. Reduce heat to medium and cook them for about 10 more minutes, making sure they are not raw inside. Remove meatballs and put them on a large plate.