If my emloyeer has slapped me on butt with towel and makes comments, do I have a case?

From what you write, you may well have a case; it would be worthwhile for you to consult with an employment law attorney, since you may be entitled to compensation:

1) Almost by definition, grabbing a woman's breasts or buttocks is sexual harassment--it's difficult to imagine any situation under which it wouldn't be.

2) Sexually charged or related, or lewd, comments would also be sexual harassment.

3) Slapping on the buttocks with a towel would likely be sexual harassment as well.

(Note that 1) to 3) could also be assault, too.)

4) Paying "under the table" is a violation of tax laws.

About the only thing you write about that's not a violation of some sort is yelling and cursing (as long as the yells and curses are not sex- or gender-related)--the law does not require employers to be courteous, respectful, professional, etc., and employers may yell at their staff.