In a small saucepan combine the rinsed 1/2 cup quinoa and 1 1/4 cups water. Bring to a boil over high heat, then reduce heat to low, cover, and simmer about 15 minutes or until the water is absorbed. Remove from heat, fluff with a fork, and let the quinoa cool completely.
While the quinoa cools, prepare the vegetables: slice the large zucchini vertically and cut the red bell pepper into strips. Set aside.
In a large bowl mash 1 cup precooked, rinsed, and drained chickpeas with a fork or potato masher until mostly broken up but still a bit textured. Add the cooled quinoa, 1 egg, 1/2 cup whole-grain bread crumbs, 1/4 cup grated Parmesan cheese, 1 medium onion (finely chopped or grated), 2 tablespoons chopped fresh parsley (of the 3 tablespoons), 1/2 teaspoon dried oregano (of the 1 teaspoon), 1/2 teaspoon sea salt (of the 3/4 teaspoon), and 1/4 teaspoon black pepper (of the 1/2 teaspoon). Mix until evenly combined.
Divide the mixture and shape into 10 mini patties (slider size). Cover and refrigerate the patties for about 2 hours to firm up.
While the patties chill, grill the vegetables: preheat a griddle or grill pan to medium-high. Cook the zucchini slices and pepper strips until tender and slightly charred (about 3–5 minutes per side for zucchini; 4–6 minutes total for pepper, turning as needed). Transfer the hot vegetables to a medium bowl and toss with 1 tablespoon extra-virgin olive oil, 1 tablespoon balsamic vinegar, the remaining 1/2 teaspoon dried oregano, the remaining 1 tablespoon chopped parsley, the remaining 1/4 teaspoon sea salt, and the remaining 1/4 teaspoon black pepper. Set the dressed vegetables aside.
After the patties have chilled, heat a large nonstick skillet or griddle over medium heat and add the remaining 2 tablespoons extra-virgin olive oil. Cook the patties in batches 3–5 minutes per side, until golden brown and heated through. Transfer cooked patties to a plate.
Using the same (clean) skillet or griddle, lightly brown the insides of the 10 whole-grain slider buns over medium heat (use any oil remaining in the pan if needed), about 30–60 seconds per side until lightly toasted.
Assemble the sliders: place a lettuce leaf on the bottom half of each bun, top with a quinoa-and-chickpea patty, add a portion of the grilled vegetables, and finish with the top bun. Serve immediately.