In a medium saucepan, heat 1 tablespoon canola oil over medium high heat. Add shallots and ginger, and cook for 1 minute, until fragrant. Add in curry paste and stir, letting it darken, for about 1 minute.
Pour in coconut milk, fish sauce, vegetable broth, coriander, and salt. Bring to a simmer, then add the broccoli. Cook for 10-15 minutes, covered, until the broccoli is tender. Remove from the heat and stir in spinach and lime juice. Let cool slightly.
Meanwhile, heat remaining canola oil in a small saucepan over high heat. Add in langostino tails and cook until just barely pink if starting with fresh or sear for about 30 seconds if defrosted. Remove from heat.
Using an immersion blender, blend the soup until smooth.
Pour soup into bowls and top soup with langostino tails, scallions, and freshly ground black pepper.