Saute your onion and garlic in a little olive oil for 4-5 minutes over medium heat, until onions begin to soften.
Stir in chickpeas, tomato sauce, water, cayenne, and curry powder.
Chop your parsley and stir that in, then cook over medium-low heat for about 20 minutes, stirring occasionally, until thickened.
It's thick enough to eat when you can scrape your chickpeas away from the sides of the skillet and the sauce doesn't immediately rush back in to fill the gap.
Notes
This gets spicier as it simmers -- it had a good kick with ½ teaspoon cayenne, but if you are sensitive to heat you might want to reduce or omit entirely.