How to Make It
In a blender, puree the sea urchin with 2 tablespoons of the olive oil until smooth.
In a pot of heavily salted boiling water, cook the linguine until al dente. Meanwhile, in a deep skillet, heat the remaining 2 tablespoons of oil. Add the ramps and cook over moderately high heat until wilted, 1 minute.
Drain the linguine, reserving 5 tablespoons of the cooking water. Add the linguine to the skillet with the sea urchin puree and 2 tablespoons of the cooking water and toss over moderate heat for 30 seconds. Off the heat, add the remaining 3 tablespoons of cooking water and toss. Transfer the linguine to bowls and serve.
Look for uni (sea urchin) at Japanese markets. If using chives, toss them with the pasta at the end.