Slice the zucchini 4" thick. Use a cookie cutter or knife to core the seedy part.
Put the sliced zucchini on a baking tray. Stuff the zucchini cavity with beans, garlic, anchovy and thyme and drizzle about 1 tablespoon oil in each slice.
Crumple a baking paper and cover the zucchini. Bake for 50 minutes. The zucchini should be tender. Remove the paper and broil for 5 minutes, to brown the dish slightly.
Make the tahini: Combine the tahini, lemon juice and ½ cup water in a small blender.
Serve: Smear the tahini on a plate and place the stuffed zucchini over it. Garnish with sumac.