In a medium saucepan combine 1/2 cup ketchup, 2 green onions (minced), 4 cloves garlic (minced), 1 lemon (juiced), 2 tablespoons honey, 1 tablespoon chili-garlic sauce, 1 teaspoon red pepper flakes, and 1/2 teaspoon black pepper. Stir to combine.
Add 1/4 cup water to the saucepan and place it over medium-high heat. Stir to incorporate the water.
Bring the mixture to a gentle simmer, then reduce the heat to medium-low.
Let the sauce simmer for about 5 minutes, stirring occasionally, until it thickens slightly and the flavors meld.
Remove the saucepan from the heat and let the sauce cool to room temperature.
Taste and season with salt to taste, stirring until the salt is dissolved.