some folks are limber enough to straddle the yak, put the paddle behind their back horizontal to the water, sit down just behind the cockpit, use the paddle to maintain balance by placing it on the deck behind them and putting one end on the ground by tilting it to one side, then lift up a leg, put it in the yak and then do the other leg, then slide into the seat.
reverse the process to get out.
however, i'm not that limber and my entrances and exits are somewhat less than graceful.
as to getting wet, get a spray skirt for winter use. keeps you dry. in the summer the water is cooling and refreshing as it drips off the paddle. and then you get to bail it out on a long paddle. it's always something...