Broil both halves of bell pepper until charred. Remove outer skin.

In food process or blender, combine roasted pepper and remaining hummus ingredients. Process until smooth, stopping to scrape down the sides as necessary and adding water a tablespoon at a time, if needed. Taste and adjust seasonings.

To prepare sandwiches, spread hummus on flatbread, leaving off about 3 inches on one side.

On the clean side, layer spinach, cucumber and tomato in that order.

Carefully roll up flatbread starting on the veggie side.

Slice roll into little pinwheels and hold together with toothpicks.

Serve with vegan tzatziki sauce for dipping.