How to get a smooth paste from ground chickpeas?
You cannot make good hummus from canned chickpeas, you should make it from fresh dried beans
The beans need plenty of soaking and rinsing
When cooking, add one tsp of baking soda per cup of beans. Baking soda chemically softens the bean proteins. Never add salt or other flavourings during the bean cooking stage

Traditional hummus is somewhat coarse, but very soft (due to baking soda). It is made with a minimal amount of olive oil, but drizzled with olive oil and a sprinkle of cooked, and still warm chick peas when served
Restaurant hummus is often just over processed junk made in a factory with a commercial grinder (like a peanut butter grinder)
Also, see How should I prepare dried chickpeas? if your chickpeas never go soft