Rinse artichokes and peel the outer layer of leaves off. Trim any sharp points remaining on leaves, and cut the stem of the artichoke off. Dice tomato and bell pepper. Prepare the garlic by giving it a good whack with the flat of your knife to remove skin and set aside.
Steam artichokes: Place about 2 inches of water along with 1 garlic clove and half of the lemon in the bottom of steamer and bring water to a gentle boil. When water is boiling, place prepared artichokes in the steamer basket and cover. Depending on the size of the artichoke, it should take about 30-45 minutes. Check tenderness of the artichoke by sinking a knife or fork tines into the bottom of the artichoke-it should easily sink in.
While the artichoke is cooking, prepare dip by pouring oil, a pinch of sea salt, cumin, sugar, juice from the other 1/2 of lemon and the 2 remaining garlic cloves in food processor or blender. Blend into smooth, thick liquid. Add bell pepper and tomato and blend again until relatively smooth, or about 1 minute. Add chickpeas and 1/4 cup of yogurt and blend thoroughly. At this point, taste it. If it is too thick, add more yogurt until you achieve desired consistency. Add more salt if desired. More sugar may be needed depending on acidity of tomato, but only add 1 pinch at a time.
Serve 2 artichokes and a separate dipping bowl to each person. Use the artichokes to scoop up dip and enjoy!
If you don't have a steamer, use a large pot with your colander as your steamer basket, but don't forget to put the lid back on! The lid does not need to fit tightly for the artichokes to still cook.
Dip can also be made ahead of time. It will keep, tightly covered, for about 1 week in refrigerator.