Soak peas overnight (or at least 8 hours), drain in the morning.
Add 1 cup of peas to 3 cups of water, bring to a boil, let simmer for about 1 hour till tender.
Heat 1 tbsp of oil in a pot over medium heat. Add the onions, saute till clear and soft.
Add the garlic and cook for about 2-3 minutes, stir frequently - until garlic is fragrant.
Transfer the garlic/onion and peas to a food processor with an 'S' blade - add the additional oil, lemon juice, salt, cumin, sumac and red pepper (if using).
Process till the dip retains some of its texture but is fairly smooth - or longer is smoother is preferred.
For a thinner dip: Add a few splashes of water or another dash of oil.
Transfer to a bowl and top with your desired toppings.
Serve the dip warm with pita, crackers, veggies, etc.
Will keep for up to 4 days in an air-tight container in the fridge.