Pour chickpeas (with liquid) into a saucepan. Cook over medium heat, stirring, until warmed through, 3 to 4 minutes. Drain.
Pulse chickpeas, garlic, lemon juice, cumin (if using), salt, and pepper in a food processor until chickpeas are mashed. With machine running, add oil gradually through food chute, and puree until smooth. Add water as needed for desired consistency. Serve with veggies.