Heat the oil in a large pot or Dutch oven over medium heat.
Add the diced onion and cook for 2 to 3 minutes, stirring until it becomes translucent.
Add the minced garlic and cook for another 30 seconds until fragrant.
Add the mountain of greens to the pot, along with the cumin, paprika, thyme, and salt.
Stir everything well to coat the greens with the seasonings.
Partially cover the pot and cook for 2 to 5 minutes, stirring frequently. The cooking time will vary depending on the type of greens used—cook just until they are wilted and tender to the bite.
Remove the pot from the heat and stir in the fresh lemon juice.
Serve immediately or at room temperature.
Don't overcrowd the pot. If you're making a very large batch, it's better to cook the greens in two separate batches to ensure they sauté rather than steam.
Add a pinch of red pepper flakes with the other spices for a gentle, warming heat.