If beets are large, peel them with a vegetable peeler and cut into large chunks. If small or medium, leave them whole or halve them. Place in a steamer basket set over boiling water. Steam, covered, until tender, 20 to 35 minutes depending on size. Lift steamer from saucepan and let beets cool. When cool enough to handle, rub off skins (if unpeeled) and trim stem and blossom ends. Cut beets into 1-inch chunks.
Combine beets, tahini, lemon juice, garlic and salt in a food processor and process until puree is creamy and smooth, scraping down sides every 30 seconds. (It may take about 2 minutes or more for mixture to become smooth.) Taste and add more lemon juice or salt, if needed.
Scrape puree into a bowl or storage container. Cover and refrigerate until ready to serve. Sprinkle with mint or dill, if using. Spread on toast or crackers or serve as a dip with pita chips or crudités, if desired.
Whole World Vegetarian