lemon juice, parmesan cheese, red pepper flakes, for serving (optional)
In a large pot, cook pasta according to package directions.
When pasta is done, drain, and reserve 1/2 cup of the starchy cooking liquid.
Return pot to stove with cooked pasta and over LOW heat, stir in pesto and reserved pasta water. Add in pasta water a few tablespoons at a time, stir and check the consistency. You don't want it too watery, you just want enough water to help incorporate the pesto. Usually about 1/4 cup does the trick.
Gently fold in tomatoes, tuna and artichoke hearts, stirring carefully to combine. Heat over low heat for a minute or so, just until everything is warmed through. Serve immediately with a good squeeze of lemon, Parmesan cheese and crushed red pepper, if you like!
Note 1: Pasta that has holes, ridges or nooks and crannies for the pesto to cling onto work best!Campanelle, Fusilli (corkscrew) and orecchiette ("ears") work best. But honestly, you can't really go wrong!Note 2: I like using the tuna packed in olive oil for the flavor, but tuna packed in water is just fine, too! I always look for "Solid White" tuna---it seems to be the freshest tasting!