Toss cooked lentils with olive oil, lemon juice, cumin, garlic, and salt. Let sit 15 to 20 minutes.
Cook grated cauliflower in olive oil for 5 to 6 minutes until softened and moisture has cooked off.
Combine marinated lentils, cauliflower, onion, garlic, smoked paprika, salt, and pepper. Mash lightly, leaving some texture.
Add chickpea flour or breadcrumbs gradually until the mixture holds together firmly.
Shape into 4 patties and chill at least 15 minutes.
Cook patties in olive oil over medium heat, 4 to 5 minutes per side, until browned.
Assemble on buns with lettuce, tomato, onion, and sauce of choice.