Drain the chickpeas, reserving 1/2 cup liquid from the can. Reserve 2 tablespoons of chickpeas for garnishing, too.
Blend the chickpeas in a food processor or blender until you have obtained a rough paste.
Add tahini, garlic, lemon juice and salt. Blend until you have a smooth purée. Add 1/4 cup reserved water, blending meanwhile. Stop the machine to check the purée for desired texture. Some like their hummus grainier, some like it very smooth and light. If you want a very light, creamy hummus, add reserved water, 1 tablespoon at a time, until you're satisfied. Don't add a lot of water at once; that may result in something more watery than you really want.
Taste the hummus. Add more salt or lemon juice if desired – again, just a little at a time. Resist the temptation to add more garlic at this time, because the garlic flavor becomes stronger over time. Leave the hummus in its blender or food processor bowl; cover and let it mellow in the refrigerator for 1/2 hour. Taste again. I find that I don't need to add garlic, but if desired, add a small, mashed garlic clove and blend again, thoroughly. Serve in a medium bowl, or several smaller bowls placed around the table. Sprinkle each bowl with pinches of paprika and/or ground cumin. Draw a circle of olive oil around the surface of the hummus. Garnish with a few reserved chickpeas.