Place strawberries in a blender, and process until smooth. Pour into a large bowl; stir in sugar. Cover and let stand 30 minutes, stirring occasionally.
Combine boiling water and gelatin in a small bowl; let stand 5 minutes or until gelatin dissolves, stirring constantly. Add the tequila and triple sec, and stir well. Stir the gelatin mixture into the strawberry mixture. Cover and chill for 10 minutes or until the mixture begins to thicken. Add yogurt (at room temperature), stirring with a wire whisk until well-blended. Divide the mixture evenly among 5 margarita glasses or large stemmed glasses; cover and chill at least 4 hours or until set.