In the food processor or blender combine the clove of garlic, the juice from two lemons (more or less depending on your taste), 1 tablespoon of salt, 1 teaspoon of cumin, and one 16oz jar of tahini. While blending drizzle in about half a cup of ice cold water. After about a minute you should see a nice fluffy tahini mixture.
Add in the 2 cans of drained and rinsed chickpeas. Blend or process for 2-3 minutes while drizzling in ½ cup of water. Check the texture, if it is a little grainy or lumpy add in the additional ½ cup of ice water, if the texture is good then you're done!
Place the hummus in a bowl. Using a spoon create a 'moat' or divot to fill with extra virgin olive oil, sprinkle the top with ground sumac and enjoy! You can also freeze this hummus, just pop it into the fridge overnight to let it thaw (option to microwave it after it thaws).