Drain the tuna and place in a medium-sized mixing bowl.
In a food processor, pulse the sundried tomatoes, shallots, spinach, olives, capers, pepper until roughly blended. Then add the red wine vinegar and olive oil and pulse until combined. Add the dressing to the tuna and toss until combined. Taste and adjust seasonings as needed. Add more olive oil if it looks dry.
Serve a scoop of lettuce, or on green salad, or make this into sandwiches.
If you buy the tuna in oil, you’ll still want to drain it, and add fresh extra virgin olive oil, but you’ll may want to start with 1 tablespoon. Also, I happen to love the mix of white and light tuna together, and prefer to buy my tuna in water, but you may have different feelings about what kind of tuna you prefer, and how you like it packed.This tuna will keep for 4 days in the fridge. Also know that if you store the tuna for a day or more it might dry out a bit as the tuna absorbs the dressing, so it might need a splash of olive oil to loosen it up. Or if you want it tangier, even a splash of vinegar, too.