I Have a job in my kitchen where I currently have vinyl flooring over slab on grade concrete, I am wondering can I put 1/4 inch backer board, warm floor system and porcelin tile over this if so how would I adhere the backer board ?

I would remove the vinyl flooring. Use a heat gun if it's glued down. You can get one for $23 at Home Depot.
Wagner Met 1220 Heat Gun - 30002 at The Home Depot (http://www.homedepot.com/h_d1/N-5yc1vZ1xr5/R-100371401/h_d2/ProductDisplay?langId=-1&storeId=10051&catalogId=10053)
This will save you some money since you won't have to put the cement backerboard down.

I agree with pattyg2. Remove vinyl tile. Also if u have dishwasher, install new tile under dishwasher. If u don't and dishwasher has to be replaced in future it will be very hard to get out.

Good luck

Chuck