Measure out your chickpeas. Dried chickpeas (that you subsequently refresh) ALWAYS taste better than tinned.
Add water and leave it to stand overnight. The bicarb helps soften the skins, this is essential for achieving the super-smooth Hummus.
The next day, drain the chickpeas, add back into a pan, add 1 more Tsp bicarb and dry fry for 1-2 minutes.
Add water and boil for 45-60 minutes, check on the water level periodically and top up if needed. This long / high boil cooking time is needed to break down the skins.
While the chickpeas are draining, blitz your garlic clove in the food processor.
Add the drained chickpeas, tahini, salt and blitz again.
Pour in olive oil to loosen, and add your lemon juice for flavour.
Stop and scrape down the sides occasionally and check the seasoning: It may need more salt or lemon juice.
Don't stick too rigidly to the quantities of seasoning I've used here, add more salt if it's bland or more lemon juice if all you can taste is garlic: don't be afraid to experiment.
Continue to blitz until the super-smooth Hummus is achieved and you're happy with the taste. Serve (nicer than I have...), it's great with fresh cut vegetables or grilled fish.