Bring a large pot to medium-high heat and add 1 tablespoon of oil. Add the onion, carrots and celery and sauté for 3 to 5 minutes, until translucent.
Add the garlic, and ginger to the pot and sauté for 1 minute, then add the turmeric, coriander, smoked paprika, crushed red pepper and salt. Cook for 1 minute more.
Place the red lentils in a fine mesh strainer and rinse them, then add them to the pot. Stir to coat the lentils with the onion and spice mixture. Add about 1 ¼ cup of the chickpeas, reserving the rest for garnish.
Add the water to the pot and turn the heat to high and bring everything to a boil, then reduce the heat to medium-low and simmer until the lentils are tender, about 15-20 minutes.
Use an immersion blender to puree the soup.
Finish by stirring in the lemon juice, and garnish with cilantro and reserved chickpeas.