Preheat a grill or grill pan to high heat.
Toss the zucchini with 2 tablespoons of olive oil, salt and pepper.
Lightly brush each slice of bread with the remaining ¼ cup of olive oil.
Grill the zucchini until each piece is charred on the outside, but still firm inside. Don't let them cook for too long or the will become mushy.
Grill the bread on each side until nicely toasted, letting some parts get a little charred.
Allow the zucchini to cool slightly, then cut it into cubes and place them in a bowl. Taste, and season with salt and pepper if needed.
In a medium sized bowl, use an electric mixer or large whisk or to whip the cream to soft peaks. Gently fold in the lemon zest, ricotta and a small pinch of salt until fully combined.
Spoon a generous dollop of the whipped ricotta on to each toast and spread it out to coat. Top with a spoonful of the grilled zucchini, then scatter and tear the mint leaves over top.
Drizzle with a little more olive oil, sprinkle with flaky sea salt and serve.