FINGERFOOD It can be so difficult to decide what to serve at a party.  In Fingerfood, Elsa Petersen-Schepelern devotes and entire book, and over 100 recipes to help you decide and prepare.  As the title implies, all the recipes are bite-size, but that doesn't mean they taste small.    These quick and easy dishes include, Plunged Shrimp with Chile Mojo, Thai Crabcakes, Samosas, Tandoori Chicken Skewers, and many more.  There are also mini desserts, drink ideas, menu suggestions (including meeting the different dietary needs of your guests) and preparation advice to take the panic out of party giving.  Suggestions are made as to catering quantities, presentation ideas-such as gorgeous containers and serving platters or baskets.    The only book you'll ever need to plan a party with no anxiety.