Salad: - Chop the roman lettuce and place them in a really big bowl. - Cut the tomatoes into 1/2 inch cubes and add to the bowl. - Slice the cucumber into thin disks and add them to the bowl (see notes below if using English Cucumber) - Thinly slice the green onions and add to the bowl. - Julienne the sweet pepper and add to the bowl. - Thinly slice the radish in half circles and add to the bowl. - Coarsely chop the parsley and add to the bowl. - Remove the mint leaves from the stalks and add them whole to the bowl. - Cut the yellow onion in half, then in half in 2 and thinly slice each quarter then add to the bowl. - Sprinkle a bit of salt, paprika and chili powder (optional) to the bowl. Now since paprika and chili powder have the same colour, then better to put the chili powder first so you would be aware of the quantity you put, then follow with the paprika. - Mix well. Dressing: - Juice the lemons (lemon zest is always optional but it surely gives a flavour) - Add a small part of the olive oil to the lemon juice then add salt and mix. Taste. Adjust olive oil and salt. Taste. Repeat, until you get a mixture that is not neutral, but leaning a little bit towards the sour taste but definitely it should not taste oily. - Add the sumac to the dressing and mix well. You will get a dark reddish juice. Pour all the juice in the vegetable bowl. Mix well and let it cool a bit in the fridge for 15 minutes before serving.