Heat 2 tbsp. oil in a medium pot over medium heat. Add the asparagus tips and sauté until crisp tender, about 2 minutes. Remove the asparagus from the pot and set aside.
To the same pot, add the onion and cook until soft and translucent. Add the garlic, thyme, chopped asparagus, beans, broth and water. Bring to a boil then reduce to a simmer and cover. Cook for 5 to 7 minutes. Turn off the heat; stir in the lemon juice, zest and salt and pepper to taste.
Using a blender, puree the soup in 2 batches. Serve hot or cold, garnished with asparagus tips, parsley, lemon zest and a drizzle of olive oil.