Tart lime is an ideal match for the sweet cake. Triple Sec, tequila, and lime juice give the glaze the flavor of a margarita. Use wooden skewers to poke holes in the cake large enough to let the glaze soak into it.
Preheat oven to 325°.
To prepare cake, lightly spoon flour into a dry measuring cup; level with a knife. Combine flour and 3/4 cup sugar, stirring with a whisk.
Place egg whites in a large bowl; beat with a mixer at high speed until foamy. Add cream of tartar and salt; beat until soft peaks form. Add 3/4 cup sugar, 2 tablespoons at a time, beating until stiff peaks form. Beat in rind, vanilla, and 1 1/2 teaspoons juice.
Sift 1/4 cup flour mixture over egg mixture; fold in. Repeat procedure with remaining flour mixture, 1/4 cup at a time.
Spoon batter into an ungreased 10-inch tube pan, spreading evenly. Break air pockets by cutting through batter with a knife. Bake at 325° for 50 minutes or until cake springs back when lightly touched. Invert pan; cool completely. Loosen cake from sides of pan using a narrow metal spatula. Invert onto plate.
To prepare glaze, combine 3 tablespoons sugar and remaining ingredients in a small saucepan; bring to a boil. Reduce heat; simmer 3 minutes or until sugar dissolves, stirring occasionally. Pierce entire surface of cake liberally with a skewer; drizzle glaze over cake. Let stand 10 minutes.