Position a rack in the upper third of the oven and heat the broiler.
Thread the shrimp, fish and scallops onto 4 metal skewers, alternating them. Drizzle with EVOO to coat and sprinkle with a little sea salt and pepper. Broil, turning occasionally, until firm and opaque, 7 to 8 minutes.
Meanwhile, heat 3 tablespoons EVOO in a large saucepot over medium heat. Add the garlic and chile pepper and cook, stirring, for 2 minutes. Add the spinach, a few handfuls at a time, and cook until wilted. Season with salt, pepper and a little nutmeg.
Arrange the spinach on a serving platter. Top with the seafood skewers and douse the spinach and seafood with the lemon juice.