Combine all ingredients for meatballs in a large bowl, mixing to combine. Be careful not to overmix.
Form into 10-12 meatballs. I like to use an ice cream scoop to keep them an even size.
Heat a large skillet over medium heat. Add 1 tbsp oil and heat for another minute.
Add the meatballs to the pan, being careful not to overcrowd. Pan sear on each side, rotating every few minutes for a total of 10 minutes, until cooked through.
While meatballs cook, combine ingredients for teriyaki sauce in a bowl and whisk together well.
When meatballs are almost done, add the teriyaki sauce to the pan and use tongs to coat the meatballs while the sauce thickens.