PREPARE bread and spreads according to their respective recipes (may be done ahead).

SLICE bread thinly (about 1/3-inch thick); use biscuit or cookie cutters to cut out a circular shape from middle of each bread slice.

TOAST bread lightly under broiler, TURNING once.

DIVIDE bread rounds into three equal portions; for each portion, carefully SPREAD on one of the three prepared spreads to just cover the round.

BOURSIN: SLICE unpeeled cucumber and radishes into thin rings; use a potato peeler to carefully SHAVE off strips of lemon peel; use a knife to pare removed peel into very thin strips; LAYER a cucumber slice and a radish slice on round; TOP with two criss-crossed lemon strips.

CHEDDAR: SLICE jalapeno in half crosswise; CUT seeds and membrane from each half; SLICE into thin rings; LAYER jalapeno ring with a slice of pimiento on each round.

SALMON: MIX cream cheese, dill weed and sour cream (use enough sour cream to make the mix spreadable); PLACE a dollop of cream cheese on each round; TOP with 3 capers.