In a blender or food processor, combine peanut butter, oil, soy sauce, garlic, sambal, and sugar until smooth. Add lemon juice to taste.
With machine running, add coconut milk or water until sauce reaches desired consistency. Garnish with scallion slices. Serve.
My sister's version
1/2 cup peanut butter
1 Tbs brown sugar
1 Tbs soy sauce
1 Tbs lemon juice (or lime)
1 clove garlic
1 Tbs ginger (fresh) or 1 tsp ginger (ground)
2 tsp lemon basil (or any kind of fresh basil)
1/2 cup hot water
Stick it all in a Cuis and blend.