No, unfortunately, unless you are a supervisor, cashier is not classified as a skilled occupation (NOC level O, A, or B), it is skill level D.
http://www5.hrsdc.gc.ca/NOC/English/NOC/2006/ProfileKeyword.aspx?val=6&val1=6611&val11=cashier&val12=0&val13=0&val14=&val15=0&val16=0