Add olive oil to a small loaf pan and use a paper towel to coat the bottom and sides of the pan. Set aside.
Add chicken broth, water, thyme, garlic and salt to a medium saucepan and bring to a boil. Slowly add the polenta into the chicken broth, whisking constantly. Continue to whisk and cook polenta for 4-5 minutes. Remove from heat. Stir in the parmesan cheese.
Pour the polenta into the loaf pan and smooth the top. Cover with plastic wrap and let cool to room temperature. Then refrigerate until firm, several hours or overnight.
In a medium bowl, combine 2 cloves of the garlic, the lemon zest, red pepper flakes, salt, pepper, and olive oil. Stir to combine. Add the shrimp and toss to coat. Set aside for 15 minutes to marinate.
In a medium bowl combine the garlic, lemon zest and juice, dijon mustard, olive oil, salt and pepper. Whisk to combine. Add the capers, sun-dried tomatoes, red onion, grape tomatoes, artichokes and parsley. Toss to combine. Set aside.
Thread the shrimp onto skewers.
Turn the polenta out onto a cutting board. Slice polenta into 1/2" thick slices. Lightly brush them with olive oil. Lightly oil the grill grates and make sure the grill is hot before adding the polenta - it can have a tendency to stick. Grill the polenta for about 3-4 minutes per side. Transfer to a serving platter.
Grill the shrimp for about 1 1/2-2 minutes per side, until pink and opaque. Transfer to a serving platter.
To serve: Arrange the polenta on a serving platter. Spoon the topping over the polenta. Arrange the shrimp skewers over the topping. Serve.
special equipment for this recipe: bamboo or metal skewers -- if using bamboo, soak in water for an hour before grilling.
If artichoke hearts are larger than bite size, cut them into smaller chunks before adding to the topping.
You may want to do a test run of grilling the polenta. Use one slice and see how it reacts to your grill. If it sticks, take extra precaution by using "Pam for grilling" or "grill" the polenta on an oiled grill pan inside.