Awakening the Spices : Place a dry, medium saucepan over medium heat. Add the whole cumin seeds and toast for 60-90 seconds, swirling the pan constantly, until they become highly fragrant. Immediately transfer the toasted seeds to a mortar and pestle. Add the garlic cloves and crush them together into a coarse, aromatic paste. If you do not have a mortar and pestle, grind the seeds in a spice grinder and mince the garlic separately.
Building the Aromatic Base : Return the saucepan to medium heat. Add the finely chopped yellow onion and the garlic-cumin paste. Sauté for 2-3 minutes, stirring frequently, until the onion softens and the aromatics are fragrant. If the mixture sticks, add a tablespoon of water to deglaze the pan.
Stewing the Beans and Vegetables : Open the cans of fava beans and pour them into a colander. Rinse thoroughly under cool water to remove any remaining canning liquid. Drain well. Add the rinsed beans to the saucepan along with the finely diced Roma tomato. Stir everything to combine. Cook for 5 minutes, allowing the flavors to meld and the beans to heat through.
Creating the Creamy Texture : Reduce the heat to low. Using a potato masher or the back of a sturdy fork, press down on about one-third of the beans in the pot. Mash them against the side of the pan until they break down, creating a naturally thick and creamy base for the stew while leaving the rest of the beans whole for texture.
Final Infusion and Seasoning : Remove the saucepan from the heat. Stir in the tahini, fresh lemon juice, chopped parsley, black pepper, and optional red pepper flakes. Mix until the tahini is fully incorporated and the sauce is smooth and uniform in color. Taste the stew, then add the 1/4 teaspoon of sea salt. Stir again and taste, adjusting with more salt or a squeeze of lemon if needed.
Plating and Finishing : Divide the warm Ful Medames among six bowls. Using the back of a spoon, create a small well in the center of each serving. Drizzle a generous half-tablespoon of extra virgin olive oil into each well. Garnish with an extra sprinkle of fresh parsley and serve immediately.