1) Used in salads. 2) Before adding the dressing

1) ''Boneh'' - construction - is one of the 39 Avot Melachot (prototype prohibited activities). Therefore, any activity in which one connects parts to make a whole object, is considered a derivative of ''Boneh'', and is prohibited. 

איסור בונה שייך גם במאכל כגון המגבן גבינה או שמדבק פירות ומשוה אותם שיהיו יפין ולכן כשחותכין בצלים עם בצים או עם חלב דג מלוח יש ליזהר שלא להשוותם וליפותם אלא יניחם כמו שהם

1) Only water heated before Shabbat may be used; one may not turn on the hot water tap on Shabbat. Some authorities permit the use of water heated by the sun on Shabbat if a heat exchanger is used. That is, the sun heats the water, then the hot water is fed inside tubes round colder water in a storage tank. The hot water for washing is then taken from the water in the storage tank. 2) The Magen Avraham rules that this applies only to dishes which contain hardened grease, which will dissolve when hot water is poured over them; actively causing something to melt on Shabbat is a violation of the prohibition called ''Molid'' (see Law 14, Note 1). Perhaps the reason that the Kitzur Shulchan Aruch extends this ruling to include all dirty dishes is because he holds that, by pouring boiling water over the dishes, one may come to cook the food or liquid on them. 3) Since the dissolved grease would not be visible in the container of hot water, it's allowed to cause it to dissolve (just like it's allowed to place ice into a cup of drink). According to those who hold that the reason for this prohibition is not only the dissolving grease, but rather the potential cooking of the substances left on the dishes, placing the hot water into a container would cool the water down to the point where it would no longer be able to cause cooking. 4) It is forbidden to squeeze liquid out of the object in which it is absorbed; this prohibition is called ''Sechitah''. 5) It is forbidden to use a sponge, washcloth or other absorbent article to wash dishes; even steel wool or synthetic scouring pads may not be used, because they trap water between their fibers. However, one may use a synthetic pad whose fibers are widely spaced and cannot trap water. 6) As a scouring agent to clean the glassware, similarly a bar of soap may not be used on Shabbat, however, liquid soap or detergent is allowed. 7) Dishes which give off a foul odor or will attract roaches, may be washed on Shabbat, even if one is not going to use them again on that Shabbat; similarly, dishes made of acid-sensitive materials, such as silver items, may be soaked in water to prevent them from becoming permanently stained. Some authorities allow washing dishes even if they are not needed, if the sight or smell of the dishes disturbs one's enjoyment of the Shabbat (Oneg Shabbat). The laws regarding immersing dishes in a Mikvah on the Shabbat and festivals are discussed in Ch. 37:13.