We are installing linoleum in the bathroom. There are tiles in there that have big gaps in them, can and?

Use a floor leveler to fill the cracks prior to linoleum. Allow it to fully cure (Usually 24 hours). Then use whatever adhesive the manufacture of the linoleum recommends. I use a Liquid Nail product as it is easy and fast not to mention very durable in wet areas. I would suggest moving the toilet for the ease of cuts, however, pretty is not what you are asking for. To finish your project trim out the sides with 3/4 quarter round.

you could scrape up the tiles or you could use under-layment with high grade construction adhesive to avoid creeks in the floor and for better adhesion. good luck