I have to use an across-the-body purse because straps keep sliding off my shoulder. Straps that slide were OK when I was able-bodied and had a free hand to keep pushing the strap back up. Fortunately I found a small purse called the Terrace Shoulder Pouch at ebag.com. Putting the purse in front of my body keeps it out of the way when I reach forward with my cane. I have larger over-the-shoulder bags, but they stick out so far I look like a pregnant walrus.
Another alternative is the smaller knife in the photo above. I think it looks like a weapon for an assassin so I use it to cut vegetables at home. I am the least fashion conscious person I know,
but even I am vain enough to want to look like everyone else in a restaurant.