In a large bowl, combine the ground chicken, ground beef, minced garlic, grated yellow onion, chopped fresh parsley, cumin, coriander, salt, and pepper.
Mix the ingredients by hand until just combined, being careful not to overwork the meat.
Divide the mixture into four equal portions and mold each portion around a wooden or metal skewer into a long, uniform cylinder shape.
Heat the extra virgin olive oil in a grill pan or cast-iron skillet over medium-high heat.
Place the skewers in the pan and grill for 4-5 minutes per side, rotating until all sides are deeply browned and the internal temperature reaches 165°F.
While the skewers cook, dice the cucumber and halve the cherry tomatoes, then toss them together in a small serving bowl.
In a separate small dish, whisk together the tahini and lemon juice with a teaspoon of water until the sauce is smooth and pourable.
Serve the hot kofta skewers immediately alongside the fresh vegetable salad and drizzle the lemon-tahini sauce over the top.