Remove excess papers from outside of garlic heads. Slice off ¼" from the top of each head of garlic (the wide/root end) to expose cloves. Discard top portion. Make a little bowl of foil to set garlic in, which will help hold the garlic cloves together and upright. Drizzle the tops with olive oil, then cover completely with foil. Roast in the oven for 40-50 minutes, or until garlic is soft throughout and lightly browned. Remove from oven and allow to cool before handling.
In a food processor, add roasted garlic cloves (discarding any papers), chickpeas, tahini, lemon juice, olive oil, salt, cumin, and cayenne pepper. Puree until smooth (up to 2 minutes), adding water as needed to reach desired consistency.
Optionally, serve topped with sesame seeds and a drizzle of olive oil.
Store leftover hummus in a sealed container in the refrigerator. Leftovers will keep for 4-5 days.