For CEC, the occupation must be skill level O, A, or B in the NOC classification -
http://www5.hrsdc.gc.ca/noc/english/noc/2006/html/Matrix.html
For administrative assistant, probably not -
http://www5.hrsdc.gc.ca/noc/english/noc/2006/ViewAllTitlesKeyword.aspx?val=1&val1=1411&val11=administrative+assistant&val12=0&val13=0&val14=&val15=0&val16=0
if the correct NOC is 14xx then no; if it is 12xx, then yes.
http://www5.hrsdc.gc.ca/noc/english/noc/2006/SearchKeywordResult.aspx?val11=administrative&val12=0&val13=0&val14=&val15=0&val16=0
As for retail sales, no -
http://www5.hrsdc.gc.ca/noc/english/noc/2006/ProfileKeyword.aspx?val=6&val1=6421&val11=retail+sales&val12=0&val13=0&val14=&val15=0&val16=0