MIX crumbs, 1/4 cup of the sugar and margarine in small bowl. Press on bottom and side of 9-inch pie plate. Bake at 350°F for 5 minutes; cool.
SPRINKLE gelatine over milk in small saucepan; let stand 1 minute. Stir on low heat until gelatine is completely dissolved, about 3 minutes. Cool slightly.
BLEND cream cheese and remaining 1/2 cup sugar in large bowl with electric mixer on medium speed until smooth. Add vanilla and lemon zest. Gradually blend in gelatine mixture on low speed until well blended. Pour into prepared crust. Refrigerate 2 to 3 hours or until firm. Garnish with strawberry slices before serving, if desired.