Place almonds on a baking sheet, and bake at 250° for 8 to 10 minutes or until warm. Slowly feed almonds through a food grinder fitted with a coarse plate. Switching to a fine grinding plate, feed almonds through grinder 3 or 4 times until smooth. Transfer to a bowl, and stir in lemon rind.
Combine 2 tablespoons water and 6 tablespoons sugar in a small saucepan; bring to a boil. Reduce heat to medium-high. Add butter and ground almonds, stirring vigorously until mixture leaves sides of pan. Transfer mixture to a small bowl. Cover and let cool 5 minutes.
Cut a lengthwise slit down center of each date to (but not through) the bottom, leaving ends intact. Mold a heaping teaspoonful of almond paste into a football shape; stuff inside date. Gently press sides until paste pushes up slightly above top of date. Pour a layer of sugar on a small plate. Roll each stuffed date in sugar. Serve immediately.
*One 7-ounce tube of almond paste may be substituted for fresh almond mixture. Knead lemon rind into paste, and proceed with recipe. You may also use a food processor or blender for grinding almonds, but results will not be as smooth. Any leftover almond paste should be covered and chilled up to 3 months. Bring to room temperature before using.