Make the aioli: In a blender, combine the chile paste, lemon juice, Dijon, salt, egg and egg yolk. Purée until smooth. With the motor running, slowly drizzle in the grapeseed oil until a thick sauce comes together. Scrape into a serving bowl and refrigerate until ready to serve.

Make the fried spring onions: Pour enough oil into a 6-quart Dutch oven to reach a depth of 2 inches. Heat the oil until a deep-fry thermometer reads 375°. Line 1 baking sheet with parchment and 1 baking sheet with paper towels, and set both aside.

Meanwhile, in a medium bowl, whisk together the flour, cornmeal, salt, garlic and onion powders. Pour the buttermilk into a shallow dish. On a cutting board, cut the spring onions into 4-inch pieces, halving the pieces with the bulbs.

Dip the spring onions into the buttermilk, then dredge in the cornmeal mixture, coating completely, and place on the parchment-lined baking sheet. Working in batches, fry the spring onions until golden brown, 4 to 5 minutes. Transfer to the paper towel-lined baking sheet to drain, and season immediately with salt.

Arrange the spring onions on a platter and serve hot with the aioli on the side.