Heat broiler to low. 

Arrange baguette slices in a single layer on a sheet pan and brush with 2 tablespoons olive oil. 

Broil 4 to 8 minutes or until light brown. Flip crostini over and brush with 2 tablespoons olive oil. Broil again for 4 to 8 minutes until brown. Set aside.3. Heat remaining 2 tablespoons olive oil in a large skillet over medium-high heat. Add onions, and sauté until they begin to soften, about 4 minutes. Add garlic, and sauté until fragrant, about 1 minute. Add zucchini, and sauté until tender but still slightly crisp, about 10 minutes. Remove from heat and stir in lemon juice, parsley, red pepper, salt, and pepper to taste.

To assemble, spread each crostini with a heaping tablespoon of chummus. Top with a large spoonful of zucchini mixture and serve.