Peel and cut sweet potatoes into 1-inch pieces. Drain and rinse chickpeas.
Set a steamer basket in a large pot; fill with enough water to come just below the basket, then bring to a boil.
Add potatoes; reduce to a simmer, cover, and cook 10-12 minutes until tender.
Transfer to a food processor and add chickpeas, lemon juice, tahini, oil, cumin, and garlic. (Add food dye if desired to make a nice red color for Valentine’s Day.)
Purée about 1 minute until smooth; thin with water if necessary.
Season with salt and pepper to taste, and let cool.
Slice bell pepper and cut the cauliflower into florets. Serve with hummus.