Begin my making the chipotle mayo. Mix all ingredients in a small bowl. Taste-test and adjust the seasonings to your liking.
To make the fritters, add the carrots, broccoli, scallions, and garlic to a large mixing bowl. Stir to evenly distribute the ingredients.
Add the flour, breadcrumbs, cumin, cayenne pepper, salt, and black pepper. Stir until well-mixed.
Stir in the lemon juice and water. Test the mixture by pressing some together in your hands. It should hold together. If the mixture is too crumbly, add a splash of water. If it's too wet, add a bit of flour.
Place a medium skillet over medium heat. Add oil to the skillet until it's about ⅛ inch deep.
When the oil begins to shimmer, shape the veggie mixture into 2-inch patties and add them directly to the skillet. Only add as many patties as you can fit without crowding the skillet.
Cook the fritters for about 4 minutes on each side, until browned and crispy. Transfer the cooked fritters to a paper towel-lined plate.
Continue cooking the fritters in batches until all of the veggie mixture has been used. Add oil to the skillet between batches as needed.
Serve the fritters with a sprinkling of chives (optional) with aioli on the side.