I'm a lefty forced to use my right hand. I deal a deck of cards with my left and wield hammers, screwdrivers and the like with my left hand. I use my right to cook and both to sew and quilt.
As for scissors I use the softtouch by fiskers. These I can switch from hand to hand with no problem. I use grey handled ones for sewing and blue ones for paper. I use the fiskers rotary cutter for right handed people in my left hand. It's a bit awkward to hold and avoid retracting the blade. I'll look into the Martinelli left handed rotary cutter.