Add the kale to a large bowl. Pour boiling water over the kale until it is fully submerged. Let the kale sit for 2-3 minutes. Then use tongs to transfer the kale into a large blender.
Add the tahini, oregano, coriander, cumin and salt to the blender. Add in the juice of one whole lemon. Don't blend until you have pasta water to add in.
Bring a large pot to a boil. Salt the water generously and cook your pasta to al dente. Reserve 2/3 cup of the salted pasta water.
Add the pasta water to the blender and blend the kale mixture until it is smooth and bright green.
Put a skillet on low heat and add the olive oil and red pepper flakes. Use tongs to transfer the pasta from the pot to the skillet, bringing a few drops of pasta water with it.
Pour in the kale sauce and stir until it evenly coats the pasta. Top with sesame seeds and serve immediately.