Place the fava beans in a small saucepan and cover with water. Simmer over medium-low heat for about 10 minutes or until the beans are tender, adding the peas about halfway through the cooking time.
Remove from heat and transfer the beans and peas to a food processor.
Add the garlic clove, lemon juice and zest, cumin, and sumac, and pulse until the beans and peas are finely chopped. Add the olive oil in a stream while the processor is running until the mixture comes together in a slightly smooth paste (I like to still be a little chunky texture), and you can add more or less olive oil depending on the texture you like.
Stir in the mint and salt and pepper, and dust with a little additional sumac if you like.
Serve with pita bread, tortilla chips, or toasted baguette slices.
Keeps refrigerated in an air-tight container for up to two days.