Peel and chop red onion, garlic and ginger. And drain and rinse the lentils.
Add oil to a pan over medium heat and add the chopped onion to it. Saute onion until it begins to slightly caramelize (about 10 minutes or so), stir often so onion doesn't burn.
Add in garlic and ginger and stir well.
Then add in the pumpkin puree, coconut milk, water, coriander, smoked paprika, and turmeric and stir well.
When all ingredients are well incorporated, add in the spinach and stir well.
Then, add in the drained and rinsed canned lentils and stir well. Let the curry cook about 5 more minutes.
Remove from the stove and season with salt and pepper to taste.
When serving, garnish with chopped cilantro and enjoy with Sri Lankan roti, naan, or rice pilaf.