Place zucchini rounds in a medium bowl, mix with salt and pepper, and toss with oil to coat.
Heat a grill pan over medium-high heat. Working in batches, roast zucchini rounds for about 1 to 2 minutes on each side, until dark lines appear. Transfer to a large bowl.
In a small bowl, mix together olive oil, lemon juice, and vinegar until combined.
Add salt, pepper, and date honey, and mix until combined.
Add garlic, onion, and parsley, and mix well.
Add peppers and mix again.
Pour pepper mixture over zucchinis, and let sit for about 30 minutes, to allow flavors to blend.
Serve at room temperature.