There isn't a filter for highest rated, but you might want to try sorting by "Buzz" -- this will put recipes with the most Notes & Ratings at the top of the list. As for newest recipes, try sorting by "Recently Added" or "Date Published". All of these options can be found in the "Sort By" drop down menu next to the search box.
As for the your second question -- if you search for wonton soup without quotation marks, you will get all recipes containing those two words anywhere in the recipe title, book title, ingredients, author's name, or categories. This could mean you get a random recipe calling for wonton wrappers from The Soup Bible, for example -- it wouldn't likely be what you are looking for, but the words wonton and soup were located somewhere in that particular recipe entry. If you search for "wonton soup" with the quoation marks, you will only get recipes containing that exact phrase somewhere in the entry which would eliminate some of the extraneous search results. However you search, priority is always given to recipes with the words or phrase you searched for in the recipe title, so those recipes would be at the top of your search results list.