Combine the tahini, maple syrup, Sriracha, soy sauce, rice vinegar, garlic, ginger, and water in a small bowl and whisk into a smooth sauce.
If the sauce is quite thick (because your tahini is thick) add 1-3 tablespoons of water to thin it to the desired consistency, keeping in mind that the tempeh will soak up most of the sauce once added.
Set the sauce aside.
Heat a large heavy-bottomed frying pan over medium-high heat.
Add the oil, and swirl to coat the bottom of the pan, and then add the tempeh.
Pan-fry the tempeh without disturbing it for about 5 minutes on one side. Once it's got a nice golden brown on the first side, flip the pieces over and give them another 5 minutes on the next side.
Reduce the heat to low and pour the sauce into the pan with the tempeh. Stir to coat it will, and set aside for 5 minutes to allow the tempeh to soak up the sauce.
To serve, spoon the tempeh and sauce into large lettuce leaves. Top with snow peas, red pepper, and a sprinkle of sesame seeds.