In a large skillet, combine ¾ cup orange marmalade, 2 tablespoons soy sauce2 teaspoons sesame oil2 teaspoons olive oil, 3 cloves garlic, 1 teaspoon ginger paste or fresh grated ginger and ¼ teaspoon red pepper flakes. Cook over medium-low heat, whisking frequently, until the sauce comes together and is begins to simmer.
While the sauce heats, whisk ⅔ cup orange juice together with 4 teaspoons cornstarch in a small bowl until smooth.
Once the sauce is simmering, pour in the orange juice slurry and whisk to combine.
Add 1 pound frozen meatballs and stir to coat. Increase the heat to medium and stir frequently until the meatballs are warmed through and the glaze has simmered and thickened, about 8–10 minutes.
Serve garnished with Sliced green onions and a side of Steamed rice, if desired.