ONION AND GARLIC: Heat the coconut oil in a large cast iron pot (nonstick will work as well, cook times are just longer since it doesn't hold/generate heat as well) over medium-high heat. Once the coconut oil has melted, add the onion and garlic; cook for 5 minutes, or until the onion becomes softened.
CHICKPEAS AND SQUASH: Add the drained and rinsed chickpeas and the cubed squash (See Note 2). Cook, still over medium heat, stirring frequently, for 7-9 minutes or until becoming tender. Using the back of a wooden spoon, crush down some of the chickpeas slightly to release the starch. This will help thicken the stew and add a nice texture.
SEASONINGS: Add in the tomato paste and cumin, chili powder, turmeric, garam masala, salt, cinnamon, cayenne pepper (optional -- leave out if sensitive to heat), and black pepper. Cook, stirring constantly, for 2 minutes or until spices are fragrant.
TOMATOES: Add in both cans of undrained crushed fire-roasted tomatoes. Cook, stirring constantly for 1 minute.
STOCK AND COUSCOUS: Add in the vegetable stock and couscous. Bring to a boil, and then reduce the heat to medium-low and simmer, covered, for 15-22 minutes or until squash is crisp-tender (it should still have some bite to it, not be mushy!) and couscous is cooked through. Stir every 3-4 minutes to keep the couscous from sticking to the bottom. If the couscous isn't cooking through or the squash is not softening, slightly increase the heat. If it's heavily boiling, slightly decrease the heat.
FINISHING: Stir in the peas to warm through. Add in the lemon juice and zest (add slowly to preference, you may not want as much as the recipe indicates) and fresh herbs. Taste and season again with salt and pepper here, I add another 1/4 teaspoon salt and 1/8 teaspoon pepper. Spoon stew into bowls and serve with a dollop of Greek yogurt if desired.