Heat oven to 350 degrees F.
in food processor, pulse graham crackers until fine crumbs are formed (about 3 cups). Add sugar and butter; pulse until crumbs are moist. Press into bottom and up side of a 9-inch springform pan. Wrap foil around bottom and up side. chill.
In a large bowl, beat cream cheese until smooth, about 1 minute. Add sugar and cornstarch; beat 2 to 3 minutes on medium-high speed until creamy. Add eggs, one at a time, beating well after each addition. Beat in Kahlua and vanilla. Pour filling into crust.
Place springform pan into large baking pan; place on oven rack and pour in hot water halfway up side of springform pan (about 6 cups).
Bake at 350 degrees F for 60 to 70 minutes or until center of cheesecake is set. Remove pan from water bath. Run knife around edge of cake and remove foil. Place on wire rack and cool completely. Cover and refrigerate overnight.
Remove side of pan. Whip cream and sugar to stiff peaks. Garnish cheesecake with whipped cream. Scatter top with coffee beans and dust with cocoa powder, if desired.