Preheat oven to 450°F (230°C). Line a large baking sheet with parchment paper.
Add pepper, cauliflower, and lentils to the baking sheet. Drizzle with 1 Tbsp (15 mL) oil and season with salt and pepper. Toss to coat and spread in an even layer.
Transfer baking sheet to preheated oven and cook, undisturbed, until cauliflower is golden brown, about 30-35 minutes.
Meanwhile, heat a medium sized saucepan over medium heat. Once hot, add 1/2 Tbsp (7 mL) oil, garlic and onion. Cook, stirring occasionally, until softened, 2-3 minutes.
Add quinoa, water, and a generous pinch of salt to the saucepan. Bring to a boil, cover and reduce heat. Simmer for about 15 minutes, or until quinoa is tender and water is absorbed. Remove from heat and let stand covered for 10 minutes, then fluff with a fork.
Remove ribs from the kale and roughly chop. Place in a bowl with 1 Tbsp (15 mL) lemon juice and remaining 1/2 Tbsp (7 mL) oil. Using your hands, massage kale until tender, about 2 minutes.
When the veggies and lentils are done, add quinoa to the baking sheet and toss to combine. Drizzle with remaining lemon juice and toss once more to coat.
Divide quinoa-veggie mix, kale, and tomatoes between 4 bowls. Top with sunflower seeds and feta. Enjoy!