Put the chopped scallions and minced ginger (with the ginger on the top, so the hot oil will sear away some of its spiciness) into a heatproof bowl and sprinkle the salt on top.
Heat the grapeseed oil in a skillet or saucepan over medium-high heat, then pour it into the bowl, letting the oil sizzle over the other ingredients. Mix well; the ginger and scallions will emit some water as everything settles. I usually let the sauce sit at room temperature for up to an hour so the flavors meld thoroughly.
You can then toss this mixture with noodles (love it with flat egg noodles) and serve with a fried egg on top! Or, the traditional way is to eat this sauce with rice and poached chicken.
Optional: garnish with a drizzle of sesame oil on top when serving.