Heat olive oil over medium high heat in saucepan. Add onion, ginger, jalapeno and garlic. Saute for several minutes, stirring constantly so they don't burn. Remove from heat; set aside.
In large stockpot, add vegetable broth, sweet potatoes, sunchokes, salt, pepper, cumin and red pepper, if using. Bring to a boil; cover, let boil for 20-30 minutes or until potatoes are fork tender. Add cilantro.
Puree in batches in a blender or use a stick immersion blender. Return to pot and serve topped with pepitas and extra cilantro, if desired.